Function IoTHubModuleClient_LL_CreateFromConnectionString 

pub unsafe extern "C" fn IoTHubModuleClient_LL_CreateFromConnectionString(
    connectionString: *const c_char,
    protocol: IOTHUB_CLIENT_TRANSPORT_PROVIDER,
) -> IOTHUB_MODULE_CLIENT_LL_HANDLE

@brief Creates a IoT Hub client for communication with an existing IoT Hub using the specified connection string parameter.

@param connectionString Pointer to a character string @param protocol Function pointer for protocol implementation

       Sample connection string:
           <blockquote>
               <pre>HostName=[IoT Hub name goes here].[IoT Hub suffix goes here, e.g., private.azure-devices-int.net];DeviceId=[Device ID goes here];SharedAccessKey=[Device key goes here];ModuleId=[Module ID goes here]</pre>
           </blockquote>

@return A non-NULL #IOTHUB_MODULE_CLIENT_LL_HANDLE value that is used when invoking other functions for IoT Hub client and @c NULL on failure.