Function writeString

ThirdParty/jsoncpp/vtkjsoncpp/jsoncpp.cpp:5338–5343

}

String writeString(StreamWriter::Factory const& factory, Value const& root) {
  OStringStream sout;
  StreamWriterPtr const writer(factory.newStreamWriter());
  writer->write(root, &sout);
  return std::move(sout).str();
}

OStream& operator<<(OStream& sout, Value const& root) {
  StreamWriterBuilder builder;