src/vs/workbench/api/common/extHostWebview.ts/ExtHostWebview/postMessage
class ExtHostWebview:	public async postMessage(message: any): Promise<boolean> {
		if (this.#isDisposed) {
			return false;
		}
		const serialized = serializeWebviewMessage(message, { serializeBuffersForPostMessage: this.#serializeBuffersForPostMessage });
		return this.#proxy.$postMessage(this.#handle, serialized.message, ...serialized.buffers);
	}