System.Net.Http.WinHttpResponseStream.ReadAsyncCore C# (CSharp) Méthode

        private async Task<int> ReadAsyncCore(byte[] buffer, int offset, int count, CancellationToken token)
        {
            _state.PinReceiveBuffer(buffer);
            var ctr = token.Register(s => ((WinHttpResponseStream)s).CancelPendingResponseStreamReadOperation(), this);
            _state.AsyncReadInProgress = true;
            try
            {
                lock (_state.Lock)
                {
                    Debug.Assert(!_requestHandle.IsInvalid);
                    if (!Interop.WinHttp.WinHttpQueryDataAvailable(_requestHandle, IntPtr.Zero))
                    {
                        throw new IOException(SR.net_http_io_read, WinHttpException.CreateExceptionUsingLastError());
                    }
                }

                int bytesAvailable = await _state.LifecycleAwaitable;

                lock (_state.Lock)
                {
                    Debug.Assert(!_requestHandle.IsInvalid);
                    if (!Interop.WinHttp.WinHttpReadData(
                        _requestHandle,
                        Marshal.UnsafeAddrOfPinnedArrayElement(buffer, offset),
                        (uint)Math.Min(bytesAvailable, count),
                        IntPtr.Zero))
                    {
                        throw new IOException(SR.net_http_io_read, WinHttpException.CreateExceptionUsingLastError());
                    }
                }

                return await _state.LifecycleAwaitable;
            }
            finally
            {
                _state.AsyncReadInProgress = false;
                ctr.Dispose();
            }
        }