From d0c202b21857745dae0667fbddaec5c4f489cd1c Mon Sep 17 00:00:00 2001
From: Georg Reinke <guelfey@gmail.com>
Date: Sun, 13 Feb 2022 12:11:21 +0100
Subject: [PATCH] conn: don't send message if context is already cancelled

---
 conn.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/conn.go b/conn.go
index 9c1fed3..69978ea 100644
--- a/conn.go
+++ b/conn.go
@@ -551,6 +551,11 @@ func (conn *Conn) send(ctx context.Context, msg *Message, ch chan *Call) *Call {
 		call.ctx = ctx
 		call.ctxCanceler = canceler
 		conn.calls.track(msg.serial, call)
+		if ctx.Err() != nil {
+			// short path: don't even send the message if context already cancelled
+			conn.calls.handleSendError(msg, ctx.Err())
+			return call
+		}
 		go func() {
 			<-ctx.Done()
 			conn.calls.handleSendError(msg, ctx.Err())