Panic: non-positive interval for NewTicker

[sybrandy]

I don't know why this occurred, but I got this error during one of my test runs:

panic: non-positive interval for NewTicker
time.NewTicker
    go/src/time/tick.go:32
github.com/gmallard/stompngo.(*Connection).receiveTicker
    src/github.com/gmallard/stompngo/heartbeats.go:163
github.com/gmallard/stompngo.(*Connection).initializeHeartBeats
    src/github.com/gmallard/stompngo/heartbeats.go:183

It only happened to me once, so it's probably something transient. Just wanted to report it as this seems like something that would be very simple to check for so that it's prevented in the future.

[gmallard]

Bizarre. Was the ticker at 500ms ?

I can see how it could happen. I will make that code a bit more defensive.

[gmallard]

On DEV: 7c54f33

[sybrandy]

Honestly, I don't recall. I waited until I was done testing to file the bug as I was focused on trying to figure out other issues.

The fix, however, looks good.