Claims the process's registration slot, synchronously: the check and the
install of the in-flight gate run without a fiber yield between them, so two
concurrent callers cannot both claim it. The claimant must call
MarkUsdidRegistrationInProcess on an accepted answer or
ReleaseUsdidRegistration otherwise.
A state object the constructor did not create cannot carry the gate: the
call dies with a clear message instead of silently dropping the guarantee.
Claims the process's registration slot, synchronously: the check and the install of the in-flight gate run without a fiber yield between them, so two concurrent callers cannot both claim it. The claimant must call MarkUsdidRegistrationInProcess on an accepted answer or ReleaseUsdidRegistration otherwise.
A state object the constructor did not create cannot carry the gate: the call dies with a clear message instead of silently dropping the guarantee.
The registration brick owns it.