Use synchronization primitives to avoid sleeping during first update

[bdraco]

Shaves off some startup time

Before
'senseme': datetime.timedelta(seconds=11, microseconds=396124),

After
'senseme': datetime.timedelta(seconds=7, microseconds=358277),

[mikelawrence]

In my testing everything still works. Note I did not test timing. I'll trust your result above.

Even if it didn't improve initial connection times this is clearly a more elegant approach. Thanks!