Function generate 

pub fn generate() -> String

A fresh identifier in the shape of a version-4 UUID.

The shape is borrowed because every log tool already knows how to spot and index it. The randomness is not cryptographic and does not pretend to be — the process-random seed the standard library hands every RandomState, stirred with a counter through SplitMix64 — which is exactly enough for two requests, on two machines, to never share an identifier by accident.