fix: add noDefaultContentType copy (#1538)

header.go

@@ -1044,6 +1044,7 @@ func (h *RequestHeader) CopyTo(dst *RequestHeader) {
 	dst.disableNormalizing = h.disableNormalizing
 	dst.noHTTP11 = h.noHTTP11
 	dst.connectionClose = h.connectionClose
+	dst.noDefaultContentType = h.noDefaultContentType
 
 	dst.contentLength = h.contentLength
 	dst.contentLengthBytes = append(dst.contentLengthBytes, h.contentLengthBytes...)

header_test.go

@@ -1342,6 +1342,7 @@ func TestRequestHeaderCopyTo(t *testing.T) {
 	h.Set(HeaderHost, "aaaa")
 	h.Set("aaaxxx", "123")
 	h.Set(HeaderTrailer, "foo, bar")
+	h.noDefaultContentType = true
 
 	var h1 RequestHeader
 	h.CopyTo(&h1)