ConstFetches the raw text of a URL through the Web Worker (or the main-thread fallback). Perf 6.3.1: Used for GPX files to offload network from the main thread. Note: DOMParser parsing stays on the main thread — it is not available in every Worker.
Checks whether the Web Worker is available.
Sets the URL the Worker is built from; null restores the default (see _detectScriptBase).
Applies to the NEXT construction: a Worker already running keeps its script until it is
torn down (idle timeout, dispose(), or an error). An error of that Worker does not
condemn the URL set here: only a failure of the URL the next Worker would use sends the
later loads to the main thread. A URL set here survives dispose() — it is configuration,
not state. Setting one also clears an earlier failure: a Worker error had sent every later
load to the main thread, and a new URL is a new attempt.
Terminates the Worker and clears its state. Called during application teardown.
Fetches and parses GeoJSON through the Web Worker (or the main-thread fallback).