Kaba class Playback ed

class Playback
    var out_changed: source
    var out_state_changed: source
    var out_tick: source
    var output_stream: shared![AudioOutput]
    var renderer: shared![SongRenderer]
    var signal_chain: shared![SignalChain]

    # constructors
    func mut __init__()

    # functions
    func get_pos() -> i32
    func is_active() -> bool
    func is_paused() -> bool
    func mut play()
    func mut prepare(r: Range, allow_loop: bool)
    func mut set_loop(loop: bool)
    func mut set_pos(pos: i32)
    func mut unsubscribe(handler: Object)