/// Switch the encoding of \p os from \p oldEnc to \p newEnc if needed.
/// \return the number of characters written to \p os.
int switchEncoding(odocstream & os, BufferParams const & bparams,
/// Switch the encoding of \p os from \p oldEnc to \p newEnc if needed.
/// \return the number of characters written to \p os.
int switchEncoding(odocstream & os, BufferParams const & bparams,