Trigger
Related Doc:
package controller
Cancels execution of the trigger.
Cancels execution of the trigger. The pusher should only do this when they're about to terminate the stream.
TODO: might be a better way to handle this, but it would probably imply we'd need to know who terminated the stream
When a user attempts to push a value into a pipe, and the pipe either fills or was already full, a Trigger is returned in the PushResult. This is essentially just a fillable callback function that is called when the pipe either becomes empty or is closed or terminated
Notice that when the trigger is executed we don't include any information about the state of the pipe. The handler can just try pushing again to determine if the pipe is dead or not.