title: setting MIDI tempo on the wire
body: <p>My electronic keyboard is periodically sending MIDI's real time clock messages, which I would like to use as a metronome in a program's of mine that sends out MIDI events to the keyboard (the purpose of this program is auto-accompaniment based on score). I get 6 such messages per quarter-note. The only thing is I couldn't find a way to set the keyboard tempo (in BPM) programmatically, that is by sending a set-tempo MIDI message from my program to the keyboard. Such a kind of message is only supported in a MIDI file and probably cannot be send on the wire. How can change the clock frequency without this feature? Changing it manually on the keyboard is unpractical.</p>
  
  <p>PS: I'm on Linux and am using blocking ALSA's snd_rawmidi_read to read bytes from the keyboard in a loop, so to synchronize my program.</p>