Meadow wifi helper to allow awaiting the wifi connection

IWiFiNetworkAdapterExtensions.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using Meadow.Hardware;

namespace MeadowHelpers {
    public static class IWiFiNetworkAdapterExtensions {
        public static async Task<NetworkConnectionEventArgs> WaitForNetworkConnection(this IWiFiNetworkAdapter wifiAdapter, string? ssid = null, string? password = null, TimeSpan timeout = default(TimeSpan), CancellationToken cancellationToken = default(CancellationToken))
        {
            var tcs = new TaskCompletionSource<NetworkConnectionEventArgs>();

            NetworkConnectionHandler? handler = null;
            handler = (networkAdapter, networkConnectionEventArgs) =>
            {
                // Unsubscribe from the event after it's been fired.
                wifiAdapter.NetworkConnected -= handler;
                tcs.SetResult(networkConnectionEventArgs);
            };
            wifiAdapter.NetworkConnected += handler;

            var wifiConnectTask = wifiAdapter.Connect(ssid, password, timeout, cancellationToken);
            _ = wifiConnectTask.ContinueWith((t) =>
            {
                if (t.IsFaulted)
                {
                    tcs.SetException(t.Exception);
                }
                else
                {
                    // Rely on .NetworkConnected event to set the result.
                }
            });

            return await tcs.Task;
        }
    }
}