Method wet

Following the call to the `Node`'s `audio_requested` method, the `Graph` will sum together some of the original (dry) signal with some of the processed (wet) signal. This method specifies the amount of the wet signal to be used (0.0 ... 1.0). By default, we want only the fully wet signal (1.0). This default is useful for generator types where we are generating a brand new signal. For processors

(&self)