The attributes were not being used currently. Since this is a private interface, remove the parameter as it makes it easier to port to Windows.
These were not in use, and removing this from the signature makes it possible to re-use the exact signature on Windows more easily.
This is in preparation to make the code here more target agnostic for porting to the Windows threading primitives. This is used pretty extensively in the tests, so disabling tests would lose a chunk of coverage.
