WIP on GPIO example

src/mesh/SinglePortPlugin.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "MeshPlugin.h"
+#include "Router.h"
 
 /**
  * Most plugins are only interested in sending/receving one particular portnum.  This baseclass simplifies that common
@@ -21,4 +22,19 @@ class SinglePortPlugin : public MeshPlugin
      * @return true if you want to receive the specified portnum
      */
     virtual bool wantPortnum(PortNum p) { return p == ourPortNum; }
+
+    /**
+     * Return a mesh packet which has been preinited as a data packet with a particular port number.
+     * You can then send this packet (after customizing any of the payload fields you might need) with
+     * service.sendToMesh()
+     */
+    MeshPacket *allocDataPacket()
+    {
+        // Update our local node info with our position (even if we don't decide to update anyone else)
+        MeshPacket *p = router->allocForSending();
+        p->decoded.which_payload = SubPacket_data_tag;
+        p->decoded.data.portnum = ourPortNum;
+
+        return p;
+    }
 };