Function parse_option_greeks 

pub fn parse_option_greeks(
    msg: &DeriveTickerMsg,
    ts_init: UnixNanos,
) -> Result<Option<OptionGreeks>>

Parses an option ticker payload into [OptionGreeks].

Returns Ok(None) when the ticker does not carry option pricing.

Errors

Returns an error when the ticker timestamp is negative or overflows.