Possibility for data loss Async UIDs? #44

I'm looking through the AsyncWrap code, and it appears that 64-bit signed int values are being cast to 32-bit signed int values here, here and here.

A few questions:

1. Am I reading this correctly?
2. Is there an alternative here? I don't immediately see how to seed a V8::Number with a 64-bit int.
3. Is 32 bits enough "space" to maintain a monotonically increasing set of unique IDs? A process running continuously for 30 days, and consuming 1657 async events per second would exhaust this space & subsequent casts would overlap with previously issued IDs.

Thanks,

Mike