The low level buffering and dispatch mechanism for messages sent by plugins on the engine side to their corresponding plugin code on the framework side.
In production, direct access to this object should not be necessary. Messages are received and dispatched by the defaultBinaryMessenger. This object is primarily used to send mock messages in tests, via the ChannelBuffers.push method (simulating a plugin sending a message to the framework).
ui.ChannelBuffers get channelBuffers => ui.channelBuffers;