int write (const MIDI::byte *msg, size_t msglen, MIDI::timestamp_t timestamp);
int read (MIDI::byte *buf, size_t bufsize);
/* waits for output to be cleared */
int write (const MIDI::byte *msg, size_t msglen, MIDI::timestamp_t timestamp);
int read (MIDI::byte *buf, size_t bufsize);
/* waits for output to be cleared */