class Concurrent::Collection::AtomicReferenceMapBackend

def get_and_set(key, value) # internalPut in the original CHMV8
  hash          = key_hash(key)
  current_table = table || initialize_table
  while true
    if !(node = current_table.volatile_get(i = current_table.hash_to_index(hash)))
      if current_table.cas_new_node(i, hash, key, value)
        increment_size
        break
      end
    elsif (node_hash = node.hash) == MOVED
      current_table = node.key
    elsif Node.locked_hash?(node_hash)
      try_await_lock(current_table, i, node)
    else
      succeeded, old_value = attempt_get_and_set(key, value, hash, current_table, i, node, node_hash)
      break old_value if succeeded
    end
  end
end