Method error_message

src/fl/task/promise_result.h:114–116

@brief Get the error message as a convenience @return Error message string, or empty string if successful @note Safe to call on success results (returns empty string)

    /// @return Error message string, or empty string if successful
    /// @note Safe to call on success results (returns empty string)
    fl::string error_message() const {
        return ok() ? fl::string() : error().message;
    }

    /// @brief Access the underlying variant (for advanced usage)
    /// @return Reference to the internal variant