public Builder mergeFrom(com.google.protobuf.DescriptorProtos.DescriptorProto.ExtensionRange other) {
          if (other == getDefaultInstance()) return this;
          if (other.hasStart()) {
            setStart(other.getStart());
          }
          if (other.hasEnd()) {
            setEnd(other.getEnd());
          }
          this.mergeUnknownFields(other.getUnknownFields());
          return this;
        }