Group chat apps don’t care about preserving functionality when the network drops. But a document editor does. And editing a message is relatively rare in chat a

Group chat apps don’t care about preserving functionality when the network drops. But a document editor does. And editing a message is relatively rare in chat apps so they can afford to lock; editing a line is common in documents and the chance of a lock conflict is higher. Your suggestion also assumes that the network is reliable. What happens if a user takes a lock and there is a partition? If the document is P2P, there is no central authority; when should the other participants override the lock? How much overhead does that add to the protocol? The main point is that there is no notion of a central clock in a distributed system; hence “lock temporally” is not precise. Relative to which participant? And what happens when messages are dropped? (Even the lock message might be dropped!) A distributed lock implementation is non-trivial. https://lamport.azurewebsites.net/pubs/time-clocks.pdf https://lamport.azurewebsites.net/pubs/time-clocks.pdf https://static.googleusercontent.com/media/research.google.com/en//archive/chubby-osdi06.pdf https://static.googleusercontent.com/media/research.google.c... https://en.m.wikipedia.org/wiki/Fallacies_of_distributed_computing https://en.m.wikipedia.org/wiki/Fallacies_of_distributed_com...