A getOrElse operator that returns a defined rate, and if this object is UndefinedRate will evaluate the
method argument.
The identifier of a MaybeRate is either -1 (undefined) or the identifier of a defined rate (>= 0).
Lifts this optional rate into an Option[Rate].
Lifts this optional rate into an Option[Rate]. An UndefinedRate becomes None, a define Rate
becomes Some.
This trait denotes an optional server calculation rate. Either the rate is explicit, Rate, or it is undefined, UndefinedRate. In the latter case, a rate is implicitly derived from the input arguments of a UGen.