Created Send D2C Message to IoT Hub (markdown)

Send-D2C-Message-to-IoT-Hub.md

@@ -0,0 +1,5 @@
+Command: **Azure IoT Hub: Send D2C message to IoT Hub**
+
+Right-click your device and select **Send D2C message to IoT Hub**, then enter the message, results will be shown in **OUTPUT > Azure IoT Toolkit** view.
+
+![send d2c](https://raw.githubusercontent.com/wiki/Microsoft/vscode-azure-iot-toolkit/images/sendd2c.gif)