sc.serveG.check()

	state, st := sc.state(f.StreamID)
	if state == http2stateIdle {
		// 6.4 "RST_STREAM frames MUST NOT be sent for a
		// stream in the "idle" state. If a RST_STREAM frame
		// identifying an idle stream is received, the
		// recipient MUST treat this as a connection error
		// (Section 5.4.1) of type PROTOCOL_ERROR.