timed wait for cyg_io_read

Is there a way to do a timed wait for cyg_io_read?  I have a thread that
is blocking on cyg_io_read and I wish to signal the thread to exit in an
orderly manner (using an event flag).  I know that I can make
cyg_io_read non-blocking and poll cyg_io_read and cyg_flag_poll but this
would burn a lot of cycles doing nothing.

Michael

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