CustomMatrix# struct CustomMatrix# Custom matrix (publish) Public Members std::string_view label# Label. std::string_view account# Account name. std::string_view exchange# Exchange. std::string_view symbol# Symbol. std::span<MatrixKey const> rows# row labels std::span<MatrixKey const> columns# column labels std::span<double const> data# matrix UpdateType update_type = {}# Update type. uint32_t version = {}# Version number (does not have to be sequential)