code: @NonNull
      @CheckResult
      public static Observable<Intent> fromIntentFilter(@NonNull final Context context,
                                                        @NonNull final IntentFilter filter) {
          return new RxBroadcastReceiver(context, filter);
      }
docs: Creates Observable that will register {@link android.content.BroadcastReceiver} for provided
  {@link IntentFilter} when subscribed to. Observable will emit received broadcast as data {@link Intent}
  
  @param context used to register broadcast receiver to.
  @param filter  {@link IntentFilter} used to select Intent broadcast to be received.