This is a discussion topic for the Ore project, DoubleJumpMixins. View the full project on Ore for downloads and more information.
DoubleJumpMixins
This mixin is used for the DoubleJump plugin, it provides a fly toggle event.
This is needed because a part of the API has not been implemented yet.
The NetHandlerPlayServer class gets modified to listen to ability (fly) changes.