Motivation:

The NIOAsyncWriter uses an atomic to generate yield IDs. Each writer has
its own atomic. We can save an allocatiuon per writer but using a shared
atomic.

Each load then wrapping increment operation with relaxed ordering takes
approx 3ns on my machine. For a UInt64 this would take approx 188 years
to wrap around if run in a tight loop.

Modification:

- Share a single yield ID counter for NIOAsyncWriter

Result:

Fewer allocations