System.Net.Sockets.SocketAsyncEventArgs.PrepareIOCPOperation C# (CSharp) Method

        private unsafe void PrepareIOCPOperation()
        {
            Debug.Assert(_currentSocket != null, "_currentSocket is null");
            Debug.Assert(_currentSocket.SafeHandle != null, "_currentSocket.SafeHandle is null");
            Debug.Assert(!_currentSocket.SafeHandle.IsInvalid, "_currentSocket.SafeHandle is invalid");

            ThreadPoolBoundHandle boundHandle = _currentSocket.SafeHandle.GetOrAllocateThreadPoolBoundHandle();

            NativeOverlapped* overlapped = null;
            if (_preAllocatedOverlapped != null)
            {
                overlapped = boundHandle.AllocateNativeOverlapped(_preAllocatedOverlapped);
                if (NetEventSource.IsEnabled) NetEventSource.Info(this, $"boundHandle:{boundHandle}, PreAllocatedOverlapped:{_preAllocatedOverlapped}, Returned:{(IntPtr)overlapped}");
            }
            else
            {
                overlapped = boundHandle.AllocateNativeOverlapped(CompletionPortCallback, this, null);
               if (NetEventSource.IsEnabled) NetEventSource.Info(this, $"boundHandle:{boundHandle}, AllocateNativeOverlapped(pinData=null), Returned:{(IntPtr)overlapped}");
            }
            Debug.Assert(overlapped != null, "NativeOverlapped is null.");

            // If we already have a SafeNativeOverlapped SafeHandle and it's associated with the same
            // socket (due to the last operation that used this SocketAsyncEventArgs using the same socket),
            // then we can reuse the same SafeHandle object.  Otherwise, this is either the first operation
            // or the last operation was with a different socket, so create a new SafeHandle.
            if (_ptrNativeOverlapped?.SocketHandle == _currentSocket.SafeHandle)
            {
                _ptrNativeOverlapped.ReplaceHandle(overlapped);
            }
            else
            {
                _ptrNativeOverlapped?.Dispose();
                _ptrNativeOverlapped = new SafeNativeOverlapped(_currentSocket.SafeHandle, overlapped);
            }
        }