You can get the state of the USER button with GetUserButton() in
C++ or Utility.getUserButton() in java.
Change-Id: I923e62cab5e621ef43fed503acab5c0d751264fb
Packing, unpacking, caching, receiving, and sending CAN messages can be done
with a thin wrapper around CANSessionMux now, removing the need for duplicated
code between different CAN devices and languages.
Change-Id: If40181e479f45a443db7a1c264437f7f89ff54d9