Function IoTHubModuleClient_SetModuleMethodCallback 

pub unsafe extern "C" fn IoTHubModuleClient_SetModuleMethodCallback(
    IoTHubClientHandle: IOTHUB_MODULE_CLIENT_HANDLE,
    methodCallback: IOTHUB_CLIENT_DEVICE_METHOD_CALLBACK_ASYNC,
    userContextCallback: *mut c_void,
) -> IOTHUB_CLIENT_RESULT

@brief This API sets callback for async cloud to module method call.

@param IoTHubClientHandle The handle created by a call to the create function. @param methodCallback The callback which will be called by IoT Hub. @param userContextCallback User specified context that will be provided to the callback. This can be @c NULL.

@return IOTHUB_CLIENT_OK upon success or an error code upon failure.