fn duplicate(&mut self) -> Option<f32> {
        let sample = if self.counter == 0 {
            self.source.next().map(|s| { self.previous = s; s })
        } else {
            Some(self.previous)
        };

        self.counter = (self.counter + 1) % self.to;
        sample
    }
// Duplicate the mono sample across all channels (e.g. from=1, to=2).
Duplicate the mono sample across all channels .
Duplicate the mono sample across all channels .
fn duplicate(&mut self) -> Option<f32> {
        let sample = if self.counter == 0 {
            self.source.next().map(|s| { self.previous = s; s })
        } else {
            Some(self.previous)
        };
        self.counter = (self.counter + 1) % self.to;
        sample
    }
fn duplicate ( & mut self ) -> Option < f32 > { let sample = if self . counter == 0 { self . source . next ( ) . map ( | s | { self . previous = s ; s } ) } else { Some ( self . previous ) } ; self . counter = ( self . counter + 1 ) % self . to ; sample }
Duplicate the mono sample across all channels (e.g.
Duplicate the mono sample across all channels ( e . g .
&mut self
&mut self