Tracer: reproduce document state at given point in time

[ulugbekna]

Hi,

As a language server developer, I sometimes would like to look at language client and server interaction and be able to see for what kind of document a certain response was sent. For example, if I see an error response for a completion request, I would like to see for what state of the document this response was sent. I am thinking of a feature in the tracer that can go from textDocument/didOpen to the current request of interest, applying all content change notifications, to reproduce the document state.

Would such a feature be welcome? Do you also experience such need?

Another feature that could be built based on this one is ability to see the code surrounding a position mentioned in a request.