Method acquire_locked

Acquires an exclusive lock for the allocator. This can be used to chain multiple operations on the allocator without having to repeatedly acquire locks for each one. # Example ``` use stalloc::SyncStalloc; let alloc = SyncStalloc::<100, 4>::new(); let lock = alloc.acquire_locked(); for _ in 0..20 { // make multiple allocations in a row unsafe { lock.allocate_blocks(5, 1) }.unwrap(); } drop(lock

(&self)