Can't figure out how to dynamically set read value on a characteristic based on central UUID

[jturner-flow]

I'm trying to implement a peripheral on a Pi that looks at the central's UUID on a willRead and figures out the reply based on some business logic. The problem is that because peripheral.write is async, there doesn't appear to be a way to dynamically change the value on a willRead in time for the response to go out.

Is there a recommended pattern to follow for this:

private func willRead(_ request: GATTReadRequest<Central>) -> ATTError? {
        logger.info("Recevied read")
        guard let peripheral else {
            return nil
        }
       /// SET THE VALUE OF THE CHARACTERISTIC
}