/// <summary>
/// See <see cref="ITransformer.ExecuteAsync()" />.
/// </summary>
public Task ExecuteAsync()
{
// Make sure this transformation has not been started already
if (_hasStarted)
{
throw new InvalidOperationException("This transformation has already been started.");
}
// Record the start of this transformation
_hasStarted = true;
// If there is a dependent transformer then start it
var dependentTask = _dependentTransformer?.ExecuteAsync();
// Create the task that we will complete when this transformation is complete
var taskCompletionSource = new TaskCompletionSource <object>();
// Create the arguments for the process function
var args = new Tuple <TaskCompletionSource <object>, Task>(taskCompletionSource, dependentTask);
// Start all the work items for this process
for (var i = 0; i < ThreadCount; ++i)
{
ThreadPool.QueueUserWorkItem(Process, args);
}
// Return the wait handle
return(taskCompletionSource.Task);
}