System.Net.FixedSizeReader.StartReading C# (CSharp) Method

        private void StartReading()
        {
            while (true)
            {
                IAsyncResult ar = _transport.BeginRead(_request.Buffer, _request.Offset + _totalRead, _request.Count - _totalRead, s_readCallback, this);
                if (!ar.CompletedSynchronously)
                {
#if DEBUG
                    _request._DebugAsyncChain = ar;
#endif
                    break;
                }

                int bytes = _transport.EndRead(ar);

                if (CheckCompletionBeforeNextRead(bytes))
                {
                    break;
                }
            }
        }

        //
        //
        //
        private static void ReadCallback(IAsyncResult transportResult)
        {
            GlobalLog.Assert(transportResult.AsyncState is FixedSizeReader, "ReadCallback|State type is wrong, expected FixedSizeReader.");
            if (transportResult.CompletedSynchronously)
            {
                return;
            }

            FixedSizeReader      reader  = (FixedSizeReader)transportResult.AsyncState;
            AsyncProtocolRequest request = reader._Request;

            // Async completion
            try
            {
                int bytes = reader._Transport.EndRead(transportResult);

                if (reader.CheckCompletionBeforeNextRead(bytes))
                {
                    return;
                }
                reader.StartReading();
            }
            catch (Exception e)
            {
                if (request.IsUserCompleted)
                {
                    throw;
                }
                request.CompleteWithError(e);
            }
        }