net/http: don't cancel Dials when requests are canceled

Currently, when a Transport creates a new connection for a request,
it uses the request's Context to make the Dial. If a request
times out or is canceled before a Dial completes, the Dial is
canceled.

Change this so that the lifetime of a Dial call is not bound
by the request that originated it.

This change avoids a scenario where a Transport can start and
then cancel many Dial calls in rapid succession:

  - Request starts a Dial.
  - A previous request completes, making its connection available.
  - The new request uses the now-idle connection, and completes.
  - The request Context is canceled, and the Dial is aborted.

Fixes #59017

Change-Id: I996ffabc56d3b1b43129cbfd9b3e9ea7d53d263c
Reviewed-on: https://go-review.googlesource.com/c/go/+/576555
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

0 files changed, 0 insertions, 0 deletions