This API allows scripts running in one tab to asynchronously acquire a lock, hold it while work is performed, then release it. While held, no other script in the origin can acquire the same lock. A lock represents some potentially shared resource, identified by a name chosen by the web app. For example, if a web app running in multiple tabs wants to ensure that only one tab is syncing to the network, each tab could try to acquire a "my_net_sync" lock, but only one tab will succeed.