+ /// Plays a wave file (blocking).
+ ///
+ /// * `path`: wave file to transmit, must be 8 kHz mono and 16-bit LE
+ /// * `tx`: a `TxHandle` obtained from an `M17App`
+ /// * `source`: address of transmission source
+ /// * `destination`: address of transmission destination
+ /// * `channel_access_number`: from 0 to 15, usually 0