/* @preserve
	2022-09-16
	
	The author disclaims copyright to this source code.  In place of a
	legal notice, here is a blessing:
	
	*   May you do good and not evil.
	*   May you find forgiveness for yourself and forgive others.
	*   May you share freely, never taking more than you give.
	
	***********************************************************************
	
	A Worker which manages asynchronous OPFS handles on behalf of a
	synchronous API which controls it via a combination of Worker
	messages, SharedArrayBuffer, and Atomics. It is the asynchronous
	counterpart of the API defined in sqlite3-vfs-opfs.js.
	
	Highly indebted to:
	
	https://github.com/rhashimoto/wa-sqlite/blob/master/src/examples/OriginPrivateFileSystemVFS.js
	
	for demonstrating how to use the OPFS APIs.
	
	This file is to be loaded as a Worker. It does not have any direct
	access to the sqlite3 JS/WASM bits, so any bits which it needs (most
	notably SQLITE_xxx integer codes) have to be imported into it via an
	initialization process.
	
	This file represents an implementation detail of a larger piece of
	code, and not a public interface. Its details may change at any time
	and are not intended to be used by any client-level code.
	
	2022-11-27: Chrome v108 changes some async methods to synchronous, as
	documented at:
	
	https://developer.chrome.com/blog/sync-methods-for-accesshandles/
	
	Firefox v111 and Safari 16.4, both released in March 2023, also
	include this.
	
	We cannot change to the sync forms at this point without breaking
	clients who use Chrome v104-ish or higher. truncate(), getSize(),
	flush(), and close() are now (as of v108) synchronous. Calling them
	with an "await", as we have to for the async forms, is still legal
	with the sync forms but is superfluous. Calling the async forms with
	theFunc().then(...) is not compatible with the change to
	synchronous, but we do do not use those APIs that way. i.e. we don't
	_need_ to change anything for this, but at some point (after Chrome
	versions (approximately) 104-107 are extinct) we should change our
	usage of those methods to remove the "await".
	*/
