Begin an event stream in parallel to the routine. If delta is non-zero, the pattern will begin that many beats after 'now', provided that now + delta is later than the next event that the Spawner will generate. The method returns the stream. This may be called from any object.
seq
Run the entire pattern and then return control to the routine.
wait
Wait dur seconds and then return control to the routine.
suspend
Find the stream in the Spawner and stop it, returns nil if the stream is not found, the stream otherwise.