Function await_withdraw_change 

pub(crate) async fn await_withdraw_change(
    client: &ClientHandleArc,
    operation_id: OperationId,
    change: Vec<OutPoint>,
)

Waits for the ecash change of a successful withdrawal to be issued.

A withdrawal is reported successful once its transaction is accepted, but the primary module issues the change from funding it asynchronously. Until then the change is missing from the balance, so callers that read the balance right after a withdrawal would see it understated by the change. The withdrawal itself has already succeeded, so a failure here is only logged.