Function parse_fill_report 

pub fn parse_fill_report(
    fill: &AxFill,
    account_id: AccountId,
    instrument: &InstrumentAny,
    ts_init: UnixNanos,
) -> Result<FillReport>

Parses an Ax fill into a Nautilus [FillReport].

AX may omit an order ID for block trades and final settlement fills. Those records receive a deterministic reconciliation ID derived from the trade ID. The special-fill classifications are optional for regular fills with an order ID.

Errors

Returns an error if:

• Price or quantity fields cannot be parsed.
• Fee parsing fails.
• Fill classification is inconsistent.
• A fill is neither explicitly special nor linked to a valid order ID.