public int readString() {
    checkType(ENCODED_STRING);
    type = MUST_READ;
    return EncodedValueCodec.readUnsignedInt(in, arg, false);
  }
Returns the type of the annotation just returned by {@link #readAnnotation()}. This method's
value is undefined unless the most recent call was to {@link #readAnnotation()}.
android/android_framework/dex-maker/src/main/java/com/android/dex/EncodedValueReader.java