Unexpected ordering

[maxcountryman]

Hi there, I'm trying to write a test that demonstrates the ULID ordering promises but am seeing some unexpected behavior every few test runs or so:

[src/models/id.rs:141] &id_0 = Ulid(1972003866952799546420484161793439825);
[src/models/id.rs:142] &id_1 = Ulid(1972003866952020694265156341296371228);
thread 'models::id::tests::test_ordering_monotonic' panicked at 'assertion failed: id_0 < id_1'

Most of the time this assertion is true but sometimes it isn't. The test is simply constructing two ULIDs one after the other and then asserting.

[dylanhart]

This assertion is only valid when Ulid instances are created by Generator since there is additional state that needs to be tracked in order to ensure that the ordering is valid.