Normally one can have very fast logging when registering a single LoggerProvider with IncludeScopes = false, where BeginScope returns a NullScope.

Now because of #723 then extra allocation occurs because the following optimization was removed:

if (loggers.Length == 1)
    return loggers[0].Logger.BeginScope(state);

If the LoggerProvider attempts to implement ISupportExternalScope (And has IncludeScopes = false), then the LoggerFactory will generate even more garbage-allocation because it forces creation of AsyncLocal-state that must be transferred when using async-threading-tasks.

Again if the above optimization was used, then one could skip the external-scope-provider-logic when only a single LoggerProvider (IncludeScopes = false would continue to work).

See also #714