src/vs/workbench/services/uriIdentity/common/uriIdentityService.ts/UriIdentityService/asCanonicalUri
class UriIdentityService:	asCanonicalUri(uri: URI): URI {

		// (1) normalize URI
		if (this._fileService.canHandleResource(uri)) {
			uri = normalizePath(uri);
		}

		// (2) find the uri in its canonical form or use this uri to define it
		let item = this._canonicalUris.get(uri);
		if (item) {
			return item.touch().uri.with({ fragment: uri.fragment });
		}

		// this uri is first and defines the canonical form
		this._canonicalUris.set(uri, new Entry(uri));
		this._checkTrim();

		return uri;
	}