960954 - We need a fast read-from-path / write-to-path

Status: NEW

(Toolkit :: Async Tooling, defect)

Description

[David Teller [:Yoric] - still alive but not very active]

Experience indicates that using OS.File.{read, writeAtomic} is not always the right thing to do:
- using OS.File.read on startup on a critical path means that we need to launch the ChromeWorker, which appears to be slow (telemetry pending on bug 960952) and OS.File itself (also slow, telemetry pending) (applications: CrashMonitor, Session Restore, possibly Add-on Manager);
- using OS.File.writeAtomic with large strings can cause sizeable jank (telemetry pending on bug 916076);
- using OS.File.read can certainly also cause sizeable jank.

The best way to resolve these issues, I believe, is to offer a native implementation of OMT read/write. At a latter stage, this implementation could be used transparently by OS.File itself in replacement for the JS implementation of OS.File.{read, writeAtomic}.