add custom dartEntrypoint

android/src/main/java/com/idlefish/flutterboost/FlutterBoost.java

@@ -183,7 +183,7 @@ public class FlutterBoost {
         }
         DartExecutor.DartEntrypoint entrypoint = new DartExecutor.DartEntrypoint(
                 FlutterMain.findAppBundlePath(),
-                "main"
+                mPlatform.dartEntrypoint()
         );
 
         flutterEngine.getDartExecutor().executeDartEntrypoint(entrypoint);
@@ -285,6 +285,9 @@ public class FlutterBoost {
                     return ConfigBuilder.this.isDebug;
                 }
 
+                @Override
+                public String dartEntrypoint() { return ConfigBuilder.this.dartEntrypoint; }
+
                 @Override
                 public String initialRoute() {
                     return ConfigBuilder.this.initialRoute;

android/src/main/java/com/idlefish/flutterboost/Platform.java

@@ -41,6 +41,8 @@ public abstract class Platform {
 
     public abstract boolean isDebug();
 
+    public abstract String dartEntrypoint();
+
     public abstract String initialRoute();
 
     public abstract List<String> shellArgs();