How to add pickup date when I create new shipment

Hi.
I created new shipment and get label successfully using this package.
But I couldn't figure out the way how to set pickup date when I create new shipment.
Anyone would be appreciate to advise me for this.
Thank you

The issue names no file, test, or entry point. Start by tracing shipment creation in the PHP package and checking the UPS API documentation for pickup-date support. Done should mean a confirmed, reproducible way to provide the pickup date, with the expected behavior documented.

Written by the indexing model from the issue text.