Function skcompress 

pub fn skcompress(
    attack_ms: Node,
    release_ms: Node,
    threshold: Node,
    ratio: Node,
    knee_width: Node,
    sidechain: Node,
    xn: Node,
) -> Node

Soft-knee compressor. Expects 7 children: attack in ms, release in ms, threshold, ratio, knee width, sidechain, and input.