[Bug Report] SendEventAsync() timed out

[fazho]

My testing code creates 4 ModuleClient objects, each with a unique transport type (So 4 clients with transport type Mqtt_Tcp_Only, Amqp_Tcp_Only, Mqtt_WebSocket_Only, Amqp_WebSocket_Only, respectively), and uses each of them to send 1 telemetry message to my IoT Hub in parallel by calling SendEventAsync(). Auth type is Sas for all of them.

The Mqtt_WebSocket_Only client has sporadic timeout issues. It's not 100% reproducible (In my test environment, it happened 41 times out of 850 total runs and the occurrences seemed very random). However, when the client called OpenAsync() but errored out due to the following exception and succeeded on retry, the subsequent SendEventAsync() call would ALWAYS time out after 4 minutes. Here is the exception from OpenAsync():

System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.

Confirmed with the server team that, when the issue happened, the server did not even get the message from the Mqtt_WebSocket_Only client, which makes me think it's a client-side timeout. The other 3 clients worked perfectly fine.

[fazho]

The timeout has nothing to do with the KeyNotFoundException.