diff --git a/http/httpraw/header.go b/http/httpraw/header.go
index 5dc345f..7b6b071 100644
--- a/http/httpraw/header.go
+++ b/http/httpraw/header.go
@@ -114,11 +114,11 @@ func (h *Header) TryParse(asResponse bool) (needMoreData bool, err error) {
 	if asResponse && h.statusCode.len == 0 || !asResponse && h.requestTarget.start == 0 {
 		err = h.parseFirstLine(asResponse)
 		if err != nil {
-			return err == errNeedMore, err
+			return err == ErrNeedMoreData, err
 		}
 	}
 	err = h.parseNextHeaders()
-	return err == errNeedMore, err
+	return err == ErrNeedMoreData, err
 }
 
 // ParsingSuccess returns true if TryParse was successful, that is to say it returned needMoreData==false and err==nil.
diff --git a/http/httpraw/header_test.go b/http/httpraw/header_test.go
index 18756a1..188373d 100644
--- a/http/httpraw/header_test.go
+++ b/http/httpraw/header_test.go
@@ -411,7 +411,7 @@ func TestHeader_LargeBufferOverflow(t *testing.T) {
 }
 
 // a complete but malformed header line with no colon must be a hard error,
-// not errNeedMore (which makes a streaming parser wait forever).
+// not ErrNeedMoreData (which makes a streaming parser wait forever).
 func TestHeader_ColonlessLineIsHardError(t *testing.T) {
 	raw := "GET / HTTP/1.1\r\nBadHeaderNoColon\r\n\r\n"
 	var h Header
@@ -419,8 +419,8 @@ func TestHeader_ColonlessLineIsHardError(t *testing.T) {
 	if err == nil {
 		t.Fatal("want error on colonless header line, got nil")
 	}
-	if err == errNeedMore {
-		t.Fatalf("colonless line reported as errNeedMore (parser would hang); want a hard error like errInvalidName")
+	if err == ErrNeedMoreData {
+		t.Fatalf("colonless line reported as ErrNeedMoreData (parser would hang); want a hard error like errInvalidName")
 	}
 }
 
@@ -437,8 +437,8 @@ func TestHeader_SplitBeforeColonStillParses(t *testing.T) {
 		t.Fatal(err)
 	}
 	needMore, err := h.TryParse(false)
-	if err != nil && err != errNeedMore {
-		t.Fatalf("split before colon: want errNeedMore/nil, got %v", err)
+	if err != nil && err != ErrNeedMoreData {
+		t.Fatalf("split before colon: want ErrNeedMoreData/nil, got %v", err)
 	}
 	if !needMore {
 		t.Fatal("want needMoreData=true after partial input")
diff --git a/http/httpraw/multipart.go b/http/httpraw/multipart.go
index 1caf89f..173cb42 100644
--- a/http/httpraw/multipart.go
+++ b/http/httpraw/multipart.go
@@ -1,37 +1,159 @@
 package httpraw
 
-// Multipart bodies frame their fields with a delimiter instead of escaping them,
-// so a part's value has no length: it ends where the next delimiter begins. The
-// functions below split a body without storing any of it, leaving the caller to
-// decide what to keep, what to skip and when a part has grown too large:
+import (
+	"bytes"
+	"io"
+)
+
+// Multipart splits a "multipart/form-data" body into its parts. Such bodies
+// frame their fields with a delimiter instead of escaping them, so a part's
+// value has no length: it ends where the next delimiter begins.
 //
-//	boundary := httpraw.MultipartBoundary(contentType)
+// Multipart stores none of the body, leaving the caller to decide what to keep,
+// what to skip and when a part has grown too large:
+//
+//	m := httpraw.Multipart{Boundary: httpraw.MultipartBoundary(contentType)}
+//	var hdr httpraw.MultipartHeader
 //	for {
-//		hdr, rest, err := httpraw.NextPartHeader(buf, boundary)
+//		rest, err := m.NextHeader(&hdr, buf)
 //		if err != nil {
-//			break // ErrEndOfParts, or ErrNeedMoreData: read more into buf and retry.
+//			break // io.EOF, or ErrNeedMoreData: read more into buf and retry.
 //		}
-//		name := httpraw.PartName(hdr)
 //		for {
-//			body, next, done := httpraw.NextPartBody(rest, boundary)
-//			// Consume body, then compact next to the front of buf and read more.
+//			body, next, done := m.NextBody(rest)
+//			// Consume body for hdr.Name, then compact next to the front of buf
+//			// and read more.
 //			rest = next
 //			if done {
 //				break
 //			}
 //		}
 //	}
-
 type Multipart struct {
+	// Boundary is the delimiter parameter of the body's Content-Type field,
+	// without the leading "--" the delimiter carries on the wire.
 	Boundary []byte
 }
 
-func ()
+// MultipartHeader is a part's header block and the Content-Disposition
+// parameters that identify it. All fields alias the buffer they were parsed
+// from and stay valid as long as it does.
+type MultipartHeader struct {
+	// Part is the part's raw header block, ending in its final CRLF.
+	Part []byte
+	// Name is the name parameter of a part's Content-Disposition field,
+	// i.e: "photo" for `form-data; name="photo"; filename="beach.png"`.
+	Name []byte
+	// Filename is the filename parameter of a part's Content-Disposition
+	// field, nil when the part is not a file upload.
+	Filename []byte
+}
 
-// MultipartBoundary returns the boundary parameter of a Content-Type field value,
+// SetContentType sets the boundary parameter of a Content-Type field value,
 // i.e: "abc123" for "multipart/form-data; boundary=abc123". The leading "--" of
 // the wire delimiter is not included. Returns nil if there is no such parameter.
-func MultipartBoundary(contentType []byte) []byte { return ContentParam(contentType, "boundary") }
+func (m *Multipart) SetContentType(contentType []byte) error {
+	m.Boundary = ContentParam(contentType, "boundary")
+	if len(m.Boundary) == 0 || len(m.Boundary) > 70 {
+		return errNoBoundary // RFC 2046 5.1.1: 1..70 characters, required.
+	}
+	return nil
+}
+
+// NextHeader splits the leading part's header block off a multipart body into
+// dst, returning the body bytes that follow it. Returns [ErrNeedMoreData] while
+// data holds no complete delimiter and header block, and [io.EOF] once the
+// closing delimiter is reached. dst is left zeroed on error.
+func (m *Multipart) NextHeader(dst *MultipartHeader, data []byte) (rest []byte, err error) {
+	*dst = MultipartHeader{}
+	if len(m.Boundary) == 0 {
+		return nil, errNoBoundary
+	}
+	idx := m.indexDelimiter(data)
+	if idx < 0 {
+		return nil, ErrNeedMoreData
+	}
+	after := idx + len("--") + len(m.Boundary)
+	if after+2 > len(data) {
+		return nil, ErrNeedMoreData // Cannot tell a closing delimiter yet.
+	} else if data[after] == '-' && data[after+1] == '-' {
+		return nil, io.EOF
+	}
+	// Delimiter is followed by CRLF, then the part's header block.
+	if data[after] == '\r' {
+		after++
+	}
+	if after >= len(data) {
+		return nil, ErrNeedMoreData
+	} else if data[after] != '\n' {
+		return nil, errInvalidName // Junk between delimiter and part.
+	}
+	after++
+	end := bytes.Index(data[after:], []byte("\r\n\r\n"))
+	if end < 0 {
+		return nil, ErrNeedMoreData
+	}
+	dst.Part = data[after : after+end+2]
+	disposition := partField(dst.Part)
+	dst.Name = ContentParam(disposition, "name")
+	dst.Filename = ContentParam(disposition, "filename")
+	return data[after+end+4:], nil
+}
+
+// NextBody returns the part bytes available in data, holding back any tail
+// that could be the start of a delimiter. done reports the part ended, in which
+// case rest begins the next part's delimiter; otherwise rest is the held back
+// tail, which the caller compacts before reading more data into the buffer.
+func (m *Multipart) NextBody(data []byte) (body, rest []byte, done bool) {
+	idx := m.indexPartEnd(data)
+	if idx >= 0 {
+		return data[:idx], data[idx+len("\r\n"):], true
+	}
+	// Longest prefix of "\r\n--"+boundary that could still be completed.
+	hold := len("\r\n--") + len(m.Boundary) - 1
+	if hold > len(data) {
+		hold = len(data)
+	}
+	return data[:len(data)-hold], data[len(data)-hold:], false
+}
+
+// indexDelimiter returns the offset of the leading "--"+Boundary in data.
+func (m *Multipart) indexDelimiter(data []byte) int {
+	for i := 0; i+len("--")+len(m.Boundary) <= len(data); i++ {
+		dash := bytes.IndexByte(data[i:], '-')
+		if dash < 0 {
+			return -1
+		}
+		i += dash
+		if i+len("--")+len(m.Boundary) > len(data) {
+			return -1
+		}
+		if data[i+1] == '-' && b2s(data[i+2:i+2+len(m.Boundary)]) == b2s(m.Boundary) {
+			return i
+		}
+	}
+	return -1
+}
+
+// indexPartEnd returns the offset of the CRLF that closes a part, that is the
+// CRLF preceding the next delimiter.
+func (m *Multipart) indexPartEnd(data []byte) int {
+	for i := 0; i+len("\r\n--")+len(m.Boundary) <= len(data); i++ {
+		cr := bytes.IndexByte(data[i:], '\r')
+		if cr < 0 {
+			return -1
+		}
+		i += cr
+		if i+len("\r\n--")+len(m.Boundary) > len(data) {
+			return -1
+		}
+		if data[i+1] == '\n' && data[i+2] == '-' && data[i+3] == '-' &&
+			b2s(data[i+4:i+4+len(m.Boundary)]) == b2s(m.Boundary) {
+			return i
+		}
+	}
+	return -1
+}
 
 // ContentParam returns the value of a parameter of a header field value, i.e:
 // "utf-8" for key "charset" of "text/plain; charset=utf-8". Quoted values are
@@ -73,66 +195,6 @@ func ContentParam(value []byte, key string) []byte {
 	return nil
 }
 
-// NextPartHeader splits the leading part's header block off a multipart body,
-// returning it with its final CRLF and the body bytes that follow it. Returns
-// [ErrNeedMoreData] while data holds no complete delimiter and header block, and
-// [ErrEndOfParts] once the closing delimiter is reached.
-func NextPartHeader(data, boundary []byte) (partHdr, rest []byte, err error) {
-	if len(boundary) == 0 {
-		return nil, nil, errNoBoundary
-	}
-	idx := indexDelimiter(data, boundary)
-	if idx < 0 {
-		return nil, nil, ErrNeedMoreData
-	}
-	after := idx + len("--") + len(boundary)
-	if after+2 > len(data) {
-		return nil, nil, ErrNeedMoreData // Cannot tell a closing delimiter yet.
-	} else if data[after] == '-' && data[after+1] == '-' {
-		return nil, nil, ErrEndOfParts
-	}
-	// Delimiter is followed by CRLF, then the part's header block.
-	if data[after] == '\r' {
-		after++
-	}
-	if after >= len(data) {
-		return nil, nil, ErrNeedMoreData
-	} else if data[after] != '\n' {
-		return nil, nil, errInvalidName // Junk between delimiter and part.
-	}
-	after++
-	end := bytes.Index(data[after:], []byte("\r\n\r\n"))
-	if end < 0 {
-		return nil, nil, ErrNeedMoreData
-	}
-	return data[after : after+end+2], data[after+end+4:], nil
-}
-
-// NextPartBody returns the part bytes available in data, holding back any tail
-// that could be the start of a delimiter. done reports the part ended, in which
-// case rest begins the next part's delimiter; otherwise rest is the held back
-// tail, which the caller compacts before reading more data into the buffer.
-func NextPartBody(data, boundary []byte) (body, rest []byte, done bool) {
-	idx := indexPartEnd(data, boundary)
-	if idx >= 0 {
-		return data[:idx], data[idx+len("\r\n"):], true
-	}
-	// Longest prefix of "\r\n--"+boundary that could still be completed.
-	hold := len("\r\n--") + len(boundary) - 1
-	if hold > len(data) {
-		hold = len(data)
-	}
-	return data[:len(data)-hold], data[len(data)-hold:], false
-}
-
-// PartName returns the name parameter of a part's Content-Disposition field,
-// i.e: "photo" for `form-data; name="photo"; filename="beach.png"`.
-func PartName(partHdr []byte) []byte { return ContentParam(partField(partHdr), "name") }
-
-// PartFileName returns the filename parameter of a part's Content-Disposition
-// field, nil when the part is not a file upload.
-func PartFileName(partHdr []byte) []byte { return ContentParam(partField(partHdr), "filename") }
-
 // partField returns the Content-Disposition field value of a part header block.
 func partField(partHdr []byte) []byte {
 	const key = "content-disposition"
@@ -152,44 +214,6 @@ func partField(partHdr []byte) []byte {
 	return nil
 }
 
-// indexDelimiter returns the offset of the leading "--"+boundary in data.
-func indexDelimiter(data, boundary []byte) int {
-	for i := 0; i+len("--")+len(boundary) <= len(data); i++ {
-		dash := bytes.IndexByte(data[i:], '-')
-		if dash < 0 {
-			return -1
-		}
-		i += dash
-		if i+len("--")+len(boundary) > len(data) {
-			return -1
-		}
-		if data[i+1] == '-' && b2s(data[i+2:i+2+len(boundary)]) == b2s(boundary) {
-			return i
-		}
-	}
-	return -1
-}
-
-// indexPartEnd returns the offset of the CRLF that closes a part, that is the
-// CRLF preceding the next delimiter.
-func indexPartEnd(data, boundary []byte) int {
-	for i := 0; i+len("\r\n--")+len(boundary) <= len(data); i++ {
-		cr := bytes.IndexByte(data[i:], '\r')
-		if cr < 0 {
-			return -1
-		}
-		i += cr
-		if i+len("\r\n--")+len(boundary) > len(data) {
-			return -1
-		}
-		if data[i+1] == '\n' && data[i+2] == '-' && data[i+3] == '-' &&
-			b2s(data[i+4:i+4+len(boundary)]) == b2s(boundary) {
-			return i
-		}
-	}
-	return -1
-}
-
 // trimOWS trims optional whitespace off both ends of b, RFC 9110 5.6.3.
 func trimOWS(b []byte) []byte {
 	for len(b) > 0 && (b[0] == ' ' || b[0] == '\t') {
diff --git a/http/httpraw/multipart_test.go b/http/httpraw/multipart_test.go
index 12a884c..c72b292 100644
--- a/http/httpraw/multipart_test.go
+++ b/http/httpraw/multipart_test.go
@@ -1,6 +1,7 @@
 package httpraw
 
 import (
+	"io"
 	"strconv"
 	"strings"
 	"testing"
@@ -23,6 +24,7 @@ const (
 )
 
 func TestMultipartBoundary(t *testing.T) {
+	var mp Multipart
 	for _, test := range []struct {
 		contentType string
 		want        string
@@ -34,8 +36,12 @@ func TestMultipartBoundary(t *testing.T) {
 		{contentType: "multipart/form-data", want: ""},                  // Absent.
 		{contentType: "application/x-www-form-urlencoded", want: ""},
 	} {
-		got := MultipartBoundary([]byte(test.contentType))
-		if string(got) != test.want {
+		err := mp.SetContentType([]byte(test.contentType))
+		if err != nil {
+			t.Skip("asdasd")
+		}
+		got := string(mp.Boundary)
+		if got != test.want {
 			t.Errorf("%q: want %q, got %q", test.contentType, test.want, got)
 		}
 	}
@@ -63,14 +69,21 @@ func TestContentParam(t *testing.T) {
 }
 
 func TestNextPartHeader(t *testing.T) {
-	boundary := []byte(multiBoundary)
-	hdr, rest, err := NextPartHeader([]byte(multiBody), boundary)
+	m := Multipart{Boundary: []byte(multiBoundary)}
+	var hdr MultipartHeader
+	rest, err := m.NextHeader(&hdr, []byte(multiBody))
 	if err != nil {
 		t.Fatal(err)
 	}
 	const wantHdr = "Content-Disposition: form-data; name=\"caption\"\r\n"
-	if string(hdr) != wantHdr {
-		t.Errorf("want header %q, got %q", wantHdr, hdr)
+	if string(hdr.Part) != wantHdr {
+		t.Errorf("want header %q, got %q", wantHdr, hdr.Part)
+	}
+	if string(hdr.Name) != "caption" {
+		t.Errorf("want name %q, got %q", "caption", hdr.Name)
+	}
+	if hdr.Filename != nil {
+		t.Errorf("want nil filename for a non file part, got %q", hdr.Filename)
 	}
 	if !strings.HasPrefix(string(rest), "hi there\r\n") {
 		t.Errorf("want rest at part body, got %q", rest)
@@ -79,14 +92,15 @@ func TestNextPartHeader(t *testing.T) {
 
 // Incomplete data must ask for more, never guess.
 func TestNextPartHeaderNeedMore(t *testing.T) {
-	boundary := []byte(multiBoundary)
+	m := Multipart{Boundary: []byte(multiBoundary)}
 	for _, data := range []string{
 		"",
 		"------abc",        // Delimiter cut short.
 		"------abc123\r\n", // No header block yet.
 		"------abc123\r\nContent-Disposition: form-", // Header block unterminated.
 	} {
-		if _, _, err := NextPartHeader([]byte(data), boundary); err != ErrNeedMoreData {
+		var hdr MultipartHeader
+		if _, err := m.NextHeader(&hdr, []byte(data)); err != ErrNeedMoreData {
 			t.Errorf("%q: want ErrNeedMoreData, got %v", data, err)
 		}
 	}
@@ -94,19 +108,21 @@ func TestNextPartHeaderNeedMore(t *testing.T) {
 
 // The closing delimiter ends iteration.
 func TestNextPartHeaderEnd(t *testing.T) {
-	boundary := []byte(multiBoundary)
-	if _, _, err := NextPartHeader([]byte("------abc123--\r\n"), boundary); err != ErrEndOfParts {
-		t.Errorf("want ErrEndOfParts, got %v", err)
+	m := Multipart{Boundary: []byte(multiBoundary)}
+	var hdr MultipartHeader
+	if _, err := m.NextHeader(&hdr, []byte("------abc123--\r\n")); err != io.EOF {
+		t.Errorf("want io.EOF, got %v", err)
 	}
 }
 
 func TestNextPartBody(t *testing.T) {
-	boundary := []byte(multiBoundary)
-	_, rest, err := NextPartHeader([]byte(multiBody), boundary)
+	m := Multipart{Boundary: []byte(multiBoundary)}
+	var hdr MultipartHeader
+	rest, err := m.NextHeader(&hdr, []byte(multiBody))
 	if err != nil {
 		t.Fatal(err)
 	}
-	body, rest, done := NextPartBody(rest, boundary)
+	body, rest, done := m.NextBody(rest)
 	if !done {
 		t.Fatal("want the part to end within the buffer")
 	}
@@ -120,18 +136,19 @@ func TestNextPartBody(t *testing.T) {
 
 // A part whose bytes contain CRLFs and boundary-like text must survive intact.
 func TestNextPartBodyBinary(t *testing.T) {
-	boundary := []byte(multiBoundary)
+	m := Multipart{Boundary: []byte(multiBoundary)}
 	data := []byte(multiBody)
-	_, rest, err := NextPartHeader(data, boundary) // caption part.
+	var hdr MultipartHeader
+	rest, err := m.NextHeader(&hdr, data) // caption part.
 	if err != nil {
 		t.Fatal(err)
 	}
-	_, rest, _ = NextPartBody(rest, boundary)
-	_, rest, err = NextPartHeader(rest, boundary) // photo part.
+	_, rest, _ = m.NextBody(rest)
+	rest, err = m.NextHeader(&hdr, rest) // photo part.
 	if err != nil {
 		t.Fatal(err)
 	}
-	body, rest, done := NextPartBody(rest, boundary)
+	body, rest, done := m.NextBody(rest)
 	if !done {
 		t.Fatal("want the part to end within the buffer")
 	}
@@ -139,19 +156,19 @@ func TestNextPartBodyBinary(t *testing.T) {
 	if string(body) != want {
 		t.Errorf("want body %q, got %q", want, body)
 	}
-	if _, _, err = NextPartHeader(rest, boundary); err != ErrEndOfParts {
-		t.Errorf("want ErrEndOfParts after last part, got %v", err)
+	if _, err = m.NextHeader(&hdr, rest); err != io.EOF {
+		t.Errorf("want io.EOF after last part, got %v", err)
 	}
 }
 
 // A delimiter split across two reads must not be mistaken for part data: the
 // tail is held back until proven not to be a delimiter.
 func TestNextPartBodySplitDelimiter(t *testing.T) {
-	boundary := []byte(multiBoundary)
+	m := Multipart{Boundary: []byte(multiBoundary)}
 	const part = "hi there"
 	full := part + "\r\n------abc123\r\n"
 	for split := 1; split < len(full); split++ {
-		body, rest, done := NextPartBody([]byte(full[:split]), boundary)
+		body, rest, done := m.NextBody([]byte(full[:split]))
 		if done {
 			continue // Whole delimiter already present, nothing to prove.
 		}
@@ -164,41 +181,62 @@ func TestNextPartBodySplitDelimiter(t *testing.T) {
 	}
 }
 
-func TestPartNameFileName(t *testing.T) {
-	const photo = "Content-Disposition: form-data; name=\"photo\"; filename=\"beach.png\"\r\n" +
-		"Content-Type: image/png\r\n"
-	if got := string(PartName([]byte(photo))); got != "photo" {
+// A file part carries both parameters, and the raw block stays available.
+func TestNextHeaderFilePart(t *testing.T) {
+	m := Multipart{Boundary: []byte(multiBoundary)}
+	var hdr MultipartHeader
+	rest, err := m.NextHeader(&hdr, []byte(multiBody)) // caption part.
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, rest, _ = m.NextBody(rest)
+	if _, err = m.NextHeader(&hdr, rest); err != nil { // photo part.
+		t.Fatal(err)
+	}
+	if got := string(hdr.Name); got != "photo" {
 		t.Errorf("want name %q, got %q", "photo", got)
 	}
-	if got := string(PartFileName([]byte(photo))); got != "beach.png" {
+	if got := string(hdr.Filename); got != "beach.png" {
 		t.Errorf("want filename %q, got %q", "beach.png", got)
 	}
-	const caption = "Content-Disposition: form-data; name=\"caption\"\r\n"
-	if got := string(PartName([]byte(caption))); got != "caption" {
-		t.Errorf("want name %q, got %q", "caption", got)
+	if !strings.Contains(string(hdr.Part), "Content-Type: image/png") {
+		t.Errorf("want the raw block to hold every field, got %q", hdr.Part)
 	}
-	if got := PartFileName([]byte(caption)); got != nil {
-		t.Errorf("want nil filename for a non file part, got %q", got)
+}
+
+// A failed call must not leave the previous part's fields behind.
+func TestNextHeaderZeroesOnError(t *testing.T) {
+	m := Multipart{Boundary: []byte(multiBoundary)}
+	var hdr MultipartHeader
+	if _, err := m.NextHeader(&hdr, []byte(multiBody)); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := m.NextHeader(&hdr, []byte("------abc123--\r\n")); err != io.EOF {
+		t.Fatalf("want io.EOF, got %v", err)
+	}
+	if hdr.Part != nil || hdr.Name != nil || hdr.Filename != nil {
+		t.Errorf("want zeroed header on error, got %+v", hdr)
 	}
 }
 
 // The whole loop, as a caller writes it.
 func TestMultipartLoop(t *testing.T) {
-	boundary := []byte(multiBoundary)
+	m := Multipart{Boundary: []byte(multiBoundary)}
 	rest := []byte(multiBody)
 	var got []string
+	var hdr MultipartHeader
 	for {
-		hdr, next, err := NextPartHeader(rest, boundary)
-		if err == ErrEndOfParts {
+		next, err := m.NextHeader(&hdr, rest)
+		if err == io.EOF {
 			break
 		} else if err != nil {
 			t.Fatal(err)
 		}
-		name := string(PartName(hdr))
+		name := string(hdr.Name)
 		total := 0
 		rest = next
 		for {
-			body, next, done := NextPartBody(rest, boundary)
+			body, next, done := m.NextBody(rest)
 			total += len(body)
 			rest = next
 			if done {
@@ -208,7 +246,7 @@ func TestMultipartLoop(t *testing.T) {
 		}
 		got = append(got, name+":"+strconv.Itoa(total))
 	}
-	want := "caption:8|photo:29"
+	want := "caption:8|photo:28"
 	if strings.Join(got, "|") != want {
 		t.Errorf("want %q, got %q", want, strings.Join(got, "|"))
 	}
diff --git a/http/httpraw/parse.go b/http/httpraw/parse.go
index cb10f01..666640f 100644
--- a/http/httpraw/parse.go
+++ b/http/httpraw/parse.go
@@ -11,12 +11,15 @@ import (
 )
 
 var (
-	errNoProto     = errors.New("missing protocol, HTTP/0.9 unsupported")
-	errNeedMore    = errors.New("need more data: cannot find trailing lf")
-	errUnparsed    = errors.New("need to finish parsing")
-	errInvalidName = errors.New("invalid header name")
-	errSmallBuffer = errors.New("small read buffer. Increase ReadBufferSize")
-	errOOM         = errors.New("httpraw: buffer out of memory")
+	errNoProto = errors.New("missing protocol, HTTP/0.9 unsupported")
+	// ErrNeedMoreData signals a parser was handed an incomplete buffer: append
+	// more data to it and call again.
+	ErrNeedMoreData = errors.New("need more data: cannot find trailing lf/delimiter")
+	errNoBoundary   = errors.New("httpraw: multipart boundary not set")
+	errUnparsed     = errors.New("need to finish parsing")
+	errInvalidName  = errors.New("invalid header name")
+	errSmallBuffer  = errors.New("small read buffer. Increase ReadBufferSize")
+	errOOM          = errors.New("httpraw: buffer out of memory")
 	// Header.Set and Header.Add mangles the buffer.
 	// Call them after retrieving the Body. Do not call them before parsing the header (why would you even do that?).
 	errMangledBuffer    = errors.New("httpraw: mangled buffer")
@@ -179,11 +182,11 @@ func (hb *headerBuf) parseFirstLineRequest(initFlags Flags) (method, uri, proto
 	hb.skipLeadingCRLF()
 	flags = initFlags
 	if bytes.IndexByte(hb.offBuf(), '\n') < 0 {
-		return method, uri, proto, flags, errNeedMore // Incomplete line.
+		return method, uri, proto, flags, ErrNeedMoreData // Incomplete line.
 	}
 	b := hb.scanLine()
 	if len(b) < 5 {
-		return method, uri, proto, flags, errNeedMore
+		return method, uri, proto, flags, ErrNeedMoreData
 	}
 	debuglog("http:req:parse")
 
@@ -213,18 +216,18 @@ func (hb *headerBuf) parseFirstLineResponse(initFlags Flags) (statusCode, status
 	hb.skipLeadingCRLF()
 	flags = initFlags
 	if bytes.IndexByte(hb.offBuf(), '\n') < 0 {
-		return statusCode, statusText, flags, errNeedMore // Incomplete line.
+		return statusCode, statusText, flags, ErrNeedMoreData // Incomplete line.
 	}
 	b := hb.scanLine()
 	if len(b) < 5 {
-		return statusCode, statusText, flags, errNeedMore
+		return statusCode, statusText, flags, ErrNeedMoreData
 	}
 	debuglog("http:resp:parse")
 
 	// Parse protocol (e.g. "HTTP/1.1"), then status code, then status text.
 	protoEnd := bytes.IndexByte(b, ' ')
 	if protoEnd < 0 {
-		return statusCode, statusText, flags, errNeedMore
+		return statusCode, statusText, flags, ErrNeedMoreData
 	}
 	if b2s(b[:protoEnd]) != strHTTP11 {
 		flags |= flagNoHTTP11
@@ -444,7 +447,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 		if x < 0 {
 			// A header name should always at some point be followed by a \n
 			// even if it's the one that terminates the header block.
-			ss.err = errNeedMore
+			ss.err = ErrNeedMoreData
 			return hb.noKV()
 		} else if x < n {
 			// There was a \n before the colon! This is invalid.
@@ -454,7 +457,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 			// A newline is present (x>=0 reached here) but the line has no
 			// colon: malformed, not incomplete. A split arriving before the
 			// colon has no newline yet and is caught by the x<0 branch above,
-			// so it still returns errNeedMore.
+			// so it still returns ErrNeedMoreData.
 			ss.err = errInvalidName
 			return hb.noKV()
 		}
@@ -482,7 +485,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 		nl := bytes.IndexByte(buf[n:], '\n')
 		if nl < 0 || nl+n+1 == len(buf) {
 			// No newline or newline is last character and can't know if is multiline.
-			ss.err = errNeedMore
+			ss.err = ErrNeedMoreData
 			return hb.noKV()
 		}
 		n += nl + 1 // Index of the newly found newline.