@Override
            public Action.Builder extend(Action.Builder builder) {
                Bundle wearableBundle = new Bundle();

                if (mFlags != DEFAULT_FLAGS) {
                    wearableBundle.putInt(KEY_FLAGS, mFlags);
                }
                if (mInProgressLabel != null) {
                    wearableBundle.putCharSequence(KEY_IN_PROGRESS_LABEL, mInProgressLabel);
                }
                if (mConfirmLabel != null) {
                    wearableBundle.putCharSequence(KEY_CONFIRM_LABEL, mConfirmLabel);
                }
                if (mCancelLabel != null) {
                    wearableBundle.putCharSequence(KEY_CANCEL_LABEL, mCancelLabel);
                }

                builder.getExtras().putBundle(EXTRA_WEARABLE_EXTENSIONS, wearableBundle);
                return builder;
            }
Apply wearable extensions to a notification action that is being built. This is
typically called by the {@link NotificationCompat.Action.Builder#extend}
method of {@link NotificationCompat.Action.Builder}.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/compat/NotificationCompat.java