One of the most annoying things about the existing messaging channels is that you can't really tell whether the message incoming is meant for your plugin, or specifically which of your plugin's requests it's a response to. To address this issue, BungeeBetterPluginMessaging adds support for unique request IDs to be appended to the subchannel when you send in a request.
For example, instead of sending in PlayerList you would send in "PlayerList::abcd1234" -- abcd1234 being the request ID. The response will come back with the same format subchannel.
These are ONLY supported for requests that actually send responses back to the originating server. Do not expect things like Connect, ConnectOther, Forward, and ForwardToPlayer to work with a request ID appended.