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 (OperationCanceledException) {
} catch (MessageTransportException) {
} finally {
token.Reset();
}
}
try {
if (_runTask.Status == TaskStatus.Running)
{
await _runTask;
}
} catch (OperationCanceledException) {
// Expected during disconnect.
} catch (MessageTransportException) {
// Possible and valid during disconnect.
}
}
