From: Damien Neil
+ The new WithoutCancel
+ function returns a copy of a context that is not canceled when the original
+ context is canceled.
+
+ The new WithDeadlineCause
+ and WithTimeoutCause
+ functions provide a way to set a context cancellation cause when a deadline or
+ timer expires. The cause may be retrieved with the
+ Cause
function.
+
+ The new AfterFunc
+ function registers a function to run after a context has been cancelled.
+