Function parse_race_runner_data 

pub fn parse_race_runner_data(
    race_id: &str,
    market_id: &str,
    rrc: &RaceRunnerChange,
    ts_event: UnixNanos,
    ts_init: UnixNanos,
) -> Option<BetfairRaceRunnerData>

Parses a single RaceRunnerChange into a BetfairRaceRunnerData.

Returns None if the runner change has no selection ID.