class Google::Cloud::Env::ComputeMetadata

def with_overrides temp_overrides
  old_overrides, old_existence = @mutex.synchronize do
    [@overrides, @existence]
  end
  begin
    @mutex.synchronize do
      @existence = nil
      @overrides = temp_overrides
    end
    yield
  ensure
    @mutex.synchronize do
      @existence = old_existence
      @overrides = old_overrides
    end
  end
end