The WithCancel, WithDeadline, and WithTimeout functions take a Context (the parent) and return a derived Context (the child) and a CancelFunc. Calling the CancelFunc cancels the child and its children, removes the parent's reference to the child, and stops any associated timers. Failing to call the CancelFunc leaks the child and its children until the parent is canceled or the timer fires.

For more information about the context package, refer to Package context at go.dev.

Example:

func _(ctx context.Context, cancel func()) {
 var ctx2 context.Context
 ctx2, cancel = context.WithCancel(ctx)
 _ = ctx2
}