Better performance for uuid4

[dan-ryan]

I was doing some performance profiling and it seems that sole is the slowest bit in our code.

I notice the code is just doing:

std::random_device rd;
std::uniform_int_distribution<uint64_t> dist(0, (uint64_t)(~0));

The performance was better when I added static:

static std::random_device rd;
static std::uniform_int_distribution<uint64_t> dist(0, (uint64_t)(~0));

Not sure if there is any side effects but seems to work fine for us.

[Edensan]

I can confirm this leads to a 2x performance improvement on my machine.
Tests seem to run fine (no collisions etc...).

Note that making the uniform static seems like overkill, does not change performance in any significant manner...

[dan-ryan]

Ah good. Yeah, it tested fine with everything I threw at it. It hasn't broken anything in our app so far :)

[r-lyeh-archived]

and then maybe clang will complain at-exit destructors once again some day (#13)!
fingers crossed! xD

[r-lyeh-archived]

Merged