Wait 5 seconds after connectivity change before sending

app/src/main/java/eu/faircode/email/ServiceSend.java

@@ -70,6 +70,7 @@ public class ServiceSend extends ServiceBase {
     private ExecutorService executor = Helper.getBackgroundExecutor(1, "send");
 
     private static final int PI_SEND = 1;
+    private static final long CONNECTIVITY_DELAY = 5000L; // milliseconds
     private static final int IDENTITY_ERROR_AFTER = 30; // minutes
 
     @Override
@@ -133,6 +134,8 @@ public class ServiceSend extends ServiceBase {
         });
 
         ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
+        lastSuitable = ConnectionHelper.getNetworkState(this).isSuitable();
+
         NetworkRequest.Builder builder = new NetworkRequest.Builder();
         builder.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET);
         cm.registerNetworkCallback(builder.build(), networkCallback);
@@ -240,6 +243,13 @@ public class ServiceSend extends ServiceBase {
             } catch (Throwable ex) {
                 Log.w(ex);
             }
+
+            // Wait for stabilization of connection
+            try {
+                Thread.sleep(CONNECTIVITY_DELAY);
+            } catch (InterruptedException ex) {
+                Log.w(ex);
+            }
         }
 
         if (suitable)