Optionalrealized_Closing PnL realized by the counter-party from this ADL fill.
Prior to v0.17.0 (exclusive) this also bundled the funding settled
on the counter-party's pre-existing position immediately before
the fill; from v0.17.0 (inclusive) onward, that funding component
is reported separately as realized_funding.
Funding settled on the counter-party's pre-existing position immediately before this ADL fill.
nullfor ADL fills executed before v0.17.0 — funding was reported as part ofrealized_pnlprior to that release.