// Split a line on whitespace, e.g. "foo bar baz" -> {"foo", "bar", "baz"}.
std::vector<std::string> split_tokens(const std::string &line);
// Split a line on whitespace, e.g. "foo bar baz" -> {"foo", "bar", "baz"}.
std::vector<std::string> split_tokens(const std::string &line);