@Override
      public final Builder setUnknownFields(
          final com.google.protobuf.UnknownFieldSet unknownFields) {
        return super.setUnknownFields(unknownFields);
      }
<code>optional string email = 3;</code>
@param value The bytes for email to set.
@return This builder for chaining.
core/src/test/java/com/alibaba/fastjson2/protobuf/PersonOuterClass.java