Function prepare_user_thread 

pub unsafe fn prepare_user_thread(
    builder: ThreadBuilder,
    entry: impl FnOnce() + Send + 'static,
    options: UserContextOptions,
) -> Result<PreparedThread, TaskError>

Prepares user architecture resources without publishing or activating the task.

Safety

entry must enter user mode only with the supplied address-space ownership and initialized architecture state. Inherited FP state must belong to the caller.