@Override
    public final boolean isInitialized() {
      byte isInitialized = memoizedIsInitialized;
      if (isInitialized == 1) return true;
      if (isInitialized == 0) return false;

      memoizedIsInitialized = 1;
      return true;
    }
<code>optional string email = 3;</code>
@return The bytes for email.
core/src/test/java/com/alibaba/fastjson2/protobuf/PersonOuterClass.java