UGenIn
An element that can be used as an input to a UGen.
This is after multi-channel-expansion, hence implementing
classes are UGenProxy (UGenOutProxy or UGen.SingleOut) and Constant.
trait Const[A1]
class ConstB
class ConstD
class ConstI
class ConstL
trait UGenProxy[A]
trait SingleOut[A]
class SingleOutImpl[A]
class UGenOutProxy[A]