They do need a millis() based timeout so that data left in the buffer after the socket closes can still be read in but the maintain doesn't sit and wait forever.

For loggers that return data "immediately" (unbuffered, data sent w/o request) read will "maintain" and look for any incoming data as long as the socket is open.  Use timedRead if you want a timeout.

For modems that buffer the response and wait for you to request data, read will stop if socket closes OR if there is no longer any data in the modem's response buffer.

And implemented for ublox

(cherry picked from commit 29dd7fd472)

Allows more flexibility downstream