Backport Http1 Graceful Shutdown Fix

[bonedaddy]

Overview

#3261 introduced a fix for slow graceful shutdowns, however it is only available in a release candidate version which introduces breaking api changes.

Suggestion

Backport the graceful shutdown fix into v0.14.27 and cut a new release allowing third-party packages like axum to implement the fix.

[seanmonstar]

This was considered a behavioral breaking change, which is why it was only included in 1.0.