refactoring plan about improve the respond ability

[dannypsnl]

Is your feature request related to a problem? Please describe.
The thread by default created with current-thread-custodian, which will slow down the whole DrRacket, particular if I'm working on some large project (not really large in normal scale, but racket level large).

The fundamental problem is

sauron/collect/record-maintainer.rkt

Line 79 in fb2eaa9

(set! cached-record (collect-from file-path)))]

, this collect-from is computation intensive operation, move it into a place worker seems reasonable.

Describe the solution you'd like

1. Make a place module
2. Create 4 workers via place module, and collect-from will be invoked via worker
3. When worker complete the job, send a message back
4. main-thread needs to forward result to correct record-maintainer

Describe alternatives you've considered
No idea

Additional context

I found (place-message-allowed? (make-record)) is #f, the reason are fields that involve (make-interval-map).

[dannypsnl]

Now I'm thinking, if interval-map cannot cross the boundary, it seems forward every message to place is more reasonable now……Though that is a big refactoring.

[dannypsnl]

Although interval-map cannot cross the boundary, the content of it can, so if each updation sent back to record-maintainer, will be a relatively simple solution.