Function IoTHubModuleClient_LL_SendEventToOutputAsync 

pub unsafe extern "C" fn IoTHubModuleClient_LL_SendEventToOutputAsync(
    iotHubModuleClientHandle: IOTHUB_MODULE_CLIENT_LL_HANDLE,
    eventMessageHandle: IOTHUB_MESSAGE_HANDLE,
    outputName: *const c_char,
    eventConfirmationCallback: IOTHUB_CLIENT_EVENT_CONFIRMATION_CALLBACK,
    userContextCallback: *mut c_void,
) -> IOTHUB_CLIENT_RESULT

@brief Asynchronous call to send the message specified by @p eventMessageHandle.

@param iotHubModuleClientHandle The handle created by a call to the create function. @param eventMessageHandle The handle to an IoT Hub message. @param outputName The name of the queue to send the message to. @param eventConfirmationCallback The callback specified by the module for receiving confirmation of the delivery of the IoT Hub message. This callback can be expected to invoke the IoTHubModuleClient_LL_SendEventAsync function for the same message in an attempt to retry sending a failing message. The user can specify a @c NULL value here to indicate that no callback is required. @param userContextCallback User specified context that will be provided to the callback. This can be @c NULL.

@warning: Do not call IoTHubModuleClient_LL_Destroy() or IoTHubModuleClient_LL_DoWork() from inside your application’s callback.

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