Consider allowing the developer to specify the size of the inbound/outbound buffers at a per-protocol level

[Scottapotamas]

This might be useful when they have multiple transports connected, say, bluetooth and ethernet/wifi, where the underlying layer has a max-packet size.

This would allow people to use large packet sizes without taking a ram hit on all the other protocols, and should improve data transfer behaviour if messages are sized according to the link's size (full eUI packets in each BLE packet) for example.

This could be done by shifting the interface's buffer to the 'developer scope' and then holding a pointer/length inside the structure. Then macros could be used to instantiate the arrays instead?