@Override
    public String getEmail() {
      Object ref = email_;
      if (ref instanceof String) {
        return (String) ref;
      } else {
        com.google.protobuf.ByteString bs =
            (com.google.protobuf.ByteString) ref;
        String s = bs.toStringUtf8();
        email_ = s;
        return s;
      }
    }
<code>optional string email = 3;</code>
@return The email.
core/src/test/java/com/alibaba/fastjson2/protobuf/PersonOuterClass.java