Missing ACKs from Azure IoT Hub SDK when Sending C2D message via Async Send() method call

**Problem Statement:**
Sporadic Missing ACKs from Azure IoT Hub when Sending Asynchronously via Java SDK
We are experiencing sporadic failures in receiving acknowledgments (ACKs) from Azure IoT Hub when using the Java SDK to send messages asynchronously.

**SDK Version:**
com.microsoft.azure.sdk.iot:iot-service-client (version: 2.1.6)

**Observation:**
No exceptions thrown.
No logs from callback handler for some messages.
Service Client appears connected and not in error state.
Problem is non-deterministic and non-reproducible consistently.

**More Description:**
Environment: Java 17
Sending Method: ServiceClient.sendEventAsync(message, callback, context)
Callback: Registered successfully; occasionally not invoked at all (neither success nor error).
Message Rate: Low to moderate (~X messages/sec)

Could you please confirm that if this is a known issue with this specific SDK version, which we use in our application?
Provide recommended practices or known limitations regarding async message sending in this context.
Suggest mechanisms to ensure reliable callback invocation, or if alternative SDK usage is advised.

More Description