type Handler struct {
// contains filtered or unexported fields
}
Handler guarantees execution of notifications after a critical section (the function passed
to a Run method), even in the presence of process termination. It guarantees exactly once
invocation of the provided notify functions.
New creates a new handler that guarantees all notify functions are run after the critical
section exits (or is interrupted by the OS), then invokes the final handler. If no final
handler is specified, the default final is `os.Exit(1)`. A handler can only be used for
one critical section.
Run ensures that any notifications are invoked after the provided fn exits (even if the
process is interrupted by an OS termination signal). Notifications are only invoked once
per Handler instance, so calling Run more than once will not behave as the user expects.
Signal is called when an os.Signal is received, and guarantees that all notifications
are executed, then the final handler is executed. This function should only be called once
per Handler instance.