for _ in 0..<bmb.piecePlaceEnum.pieceNumber() {
    let builder = SimpleCircleButtonBuilder.init()
    
    // Event closure when the boom-button corresponding the builder itself is clicked.
    builder.clickedClosure = { (index: Int) -> Void in
        // the boom-button is clicked
    }
    bmb.addBuilder(builder)
}

...
bmb.boomDelegate = self
...
func boomMenuButton(_ bmb: BoomMenuButton, didClickBoomButtonOfBuilder builder: BoomButtonBuilder, at
index: Int) {
    // If you have implement clickedClosures for boom-buttons in builders,
    // then you shouldn't add any listener here for duplicate callbacks.
    // buttonLabel.text = builder.normalImageName
}
func boomMenuButtonDidClickBackground(boomMenuButton bmb: BoomMenuButton) {
    animationLabel.text = "Click background!!!"
}
func boomMenuButtonWillReboom(boomMenuButton bmb: BoomMenuButton) {
    animationLabel.text = "Will RE-BOOM!!!";
}
func boomMenuButtonDidReboom(boomMenuButton bmb: BoomMenuButton) {
    animationLabel.text = "Did RE-BOOM!!!"
}
func boomMenuButtonWillBoom(boomMenuButton bmb: BoomMenuButton) {
    animationLabel.text = "Will BOOM!!!"
}
func boomMenuButtonDidBoom(boomMenuButton bmb: BoomMenuButton) {
    animationLabel.text = "Did BOOM!!!"
}

bmb.isAnimating()  // Whether BMB is animating.
bmb.isBoomed()     // Whether BMB is boomed.
bmb.isReBoomed()   // Whether BMB is re-boomed.