Extension for easy testing of async code

DispatchQueue+Util.swift

// Copyright 2022 Confusion Studios LLC
// by Dan Rosenstark
import Foundation

/// Extension on DispatchQueue? for Testing
/// If you don't have a DispatchQueue, run immediately (on current queue)
extension Optional where Wrapped : DispatchQueue {
    public func asyncIfNotNil(execute block: @escaping ()->()) {
        if let self = self {
            self.async(execute: block)
        } else {
            // should only happen in DEBUG (for testing)
            block()
        }
    }
}