# EventChannel.off(string eventName, function fn)
Start from base library version 2.7.3. Please remaining backward compatible.
with Promise style call: Not supported
Mini Program plugin: Support
Cancel listening on an event. When the second argument is given, cancel only the given listener function, otherwise cancel all listener functions
# parameter
# string eventName
Event Name
# function fn
Event listener function
# parameter
# any args
Trigger event parameter