t.Header = rr.Header
		t.Trailer = rr.Trailer
		t.Body = rr.Body
		t.BodyCloser = rr.Body
		t.ContentLength = rr.outgoingLength()
		if t.ContentLength < 0 && len(t.TransferEncoding) == 0 && t.shouldSendChunkedRequestBody() {
			t.TransferEncoding = []string{"chunked"}
		}
		// If there's a body, conservatively flush the headers
		// to any bufio.Writer we're writing to, just in case

// method is one that typically does not involve a request body.
// This is used by the Transport (via
// transferWriter.shouldSendChunkedRequestBody) to determine whether
// we try to test-read a byte from a non-nil Request.Body when
// Request.outgoingLength() returns -1. See the comments in
// shouldSendChunkedRequestBody.
func requestMethodUsuallyLacksBody(method string) bool {
	switch method {