A Listener
object provides a simple, programmatically
controlled HTTP protocol listener.
FUN
Returns function response.
event
Returns event type.
initialize(FUN, event)
Sets instance object function and event state.
new()
Listener$new(event, FUN, ...)
clone()
The objects of this class are cloneable with this method.
Listener$clone(deep = FALSE)
deep
Whether to make a deep clone.