/// <summary>
/// Synchronously flushes all logger's output buffers (which implement <see cref="IFlushableLogReceiver"/>)
/// </summary>
public static Task FlushAllAsync()
{
IEnumerable <IFlushableLogReceiver> flushableLogReceivers;
lock (LockObject)
{
flushableLogReceivers = Receivers.OfType <IFlushableLogReceiver>();
}
var flushTasks = flushableLogReceivers.Select(r => r.FlushAsync()).ToArray();
return(Task.WhenAll(flushTasks));
}