Microsoft.R.Host.Client.RHost.DisconnectAsync C# (CSharp) Method

        public async Task DisconnectAsync() {
            if (_runTask == null) {
                return;
            }

            await TaskUtilities.SwitchToBackgroundThread();

            // We may get MessageTransportException from any concurrent SendAsync or ReceiveAsync when the host
            // drops connection after we request it to do so. To ensure that those don't bubble up to the
            // client, cancel this token to indicate that we're shutting down the host - SendAsync and
            // ReceiveAsync will take care of wrapping any WSE into OperationCanceledException.
            _cts.Cancel();
            var token = await _disconnectLock.WaitAsync();
            if (!token.IsSet) {
                try {
                    // Don't use _cts, since it's already cancelled. We want to try to send this message in
                    // any case, and we'll catch MessageTransportException if no-one is on the other end anymore.
                    await _transport.CloseAsync();
                    token.Set();
                } catch (Exception ex) when (ex is OperationCanceledException || ex is MessageTransportException) {
                    token.Set();
                } finally {
                    token.Reset();
                }
            }

            try {
                await _runTask;
            } catch (OperationCanceledException) {
                // Expected during disconnect.
            } catch (MessageTransportException) {
                // Possible and valid during disconnect.
            }
        }