Ticks are not guaranteed to be delivered in the event of slow receivers:

<quote ref="https://godoc.org/time#NewTicker

">
It adjusts the intervals or drops ticks to make up for slow receivers.
</quote>

Also remove unnecessary casts of numeric constants.

Change-Id: I7c85cf2435bd044231e542de106098e0eadd5312
Signed-off-by: Matthew Sykes <sykesmat@us.ibm.com>