Addon Manager: Improve startup speed

src/Mod/AddonManager/NetworkManager.py

@@ -146,6 +146,9 @@ if HAVE_QTNETWORK:
             self.synchronous_complete: Dict[int, bool] = {}
             self.synchronous_result_data: Dict[int, QtCore.QByteArray] = {}
 
+            # Make sure we exit nicely on quit
+            QtCore.QCoreApplication.instance().aboutToQuit.connect(self.aboutToQuit)
+
         def run(self):
             """Do not call directly: use start() to begin the event loop on a new thread."""
 
@@ -257,6 +260,10 @@ if HAVE_QTNETWORK:
                     pass
                 QtCore.QCoreApplication.processEvents()
 
+        def aboutToQuit(self):
+            self.requestInterruption()
+
+
         def submit_unmonitored_get(self, url: str) -> int:
             """Adds this request to the queue, and returns an index that can be used by calling code
             in conjunction with the completed() signal to handle the results of the call. All data is
@@ -506,14 +513,18 @@ else:  # HAVE_QTNETWORK is false:
             pass  # Nothing to do
 
 
-AM_NETWORK_MANAGER = NetworkManager()
-AM_NETWORK_MANAGER.start()
-
+def InitializeNetworkManager():
+    global AM_NETWORK_MANAGER
+    if AM_NETWORK_MANAGER is None:
+        AM_NETWORK_MANAGER = NetworkManager()
+        AM_NETWORK_MANAGER.start()
 
 if __name__ == "__main__":
 
     app = QtCore.QCoreApplication()
 
+    InitializeNetworkManager()
+
     count = 0
 
     # For testing, create several network requests and send them off in quick succession: