}

	// check that type already in binary is found
	type T1 int
	checkSameType(t, ChanOf(BothDir, TypeOf(T1(1))), (chan T1)(nil))

	// Check arrow token association in undefined chan types.
	var left chan<- chan T
	var right chan (<-chan T)
	tLeft := ChanOf(SendDir, ChanOf(BothDir, TypeOf(T(""))))
	tRight := ChanOf(BothDir, ChanOf(RecvDir, TypeOf(T(""))))
	if tLeft != TypeOf(left) {

	// written.
	trailers []string

	handlerDone atomic.Bool // set true when the handler exits

	// Buffers for Date, Content-Length, and status code
	dateBuf   [len(TimeFormat)]byte
	clenBuf   [10]byte
	statusBuf [3]byte

	// closeNotifyCh is the channel returned by CloseNotify.
	// TODO(bradfitz): this is currently (for Go 1.8) always
	// non-nil. Make this lazily-created again as it used to be?