Support SharedWorker

[derekperkins]

Today, to instantiate duckdb-wasm, you pass in a Worker

// Instantiate the asynchronous version of DuckDB-wasm
const worker = new Worker(bundle.mainWorker!);
const logger = new duckdb.ConsoleLogger();
const db = new duckdb.AsyncDuckDB(logger, worker);

It would be great if we could pass in a SharedWorker, to synchronize access across tabs. This would make things much less memory hungry, and would be very helpful to synchronize OPFS writes.

duckdb-wasm/packages/duckdb-wasm/src/parallel/async_bindings.ts

Lines 53 to 58 in ff93f70

	constructor(logger: Logger, worker: Worker | null = null) {
	this._logger = logger;
	this._onMessageHandler = this.onMessage.bind(this);
	this._onErrorHandler = this.onError.bind(this);
	this._onCloseHandler = this.onClose.bind(this);
	if (worker != null) this.attach(worker);