@Override
	public boolean exists(String filename, TaskMonitor monitor) {
		try {
			HttpRequest request = request(filename)
					.timeout(Duration.ofMillis(HTTP_REQUEST_TIMEOUT_MS))
					.method("HEAD", BodyPublishers.noBody())
					.build();

			Msg.debug(this,
				logPrefix() + ": Checking exist for [" + filename + "]: " + request.toString());
			HttpResponse<Void> response =
				HttpClients.getHttpClient().send(request, BodyHandlers.discarding());
			int statusCode = response.statusCode();
			Msg.debug(this, logPrefix() + ": Response: " + response.statusCode());

			return statusCode == HTTP_STATUS_OK;
		}
		catch (InterruptedException | IOException e) {
			// ignore, return false
			return false;
		}
	}
Creates a new instance of a HttpSymbolServer.

@param serverURI URI / URL of the symbol server 
@param isTrusted flag, if true the http server can be trusted when querying and downloading
Ghidra/Features/PDB/src/main/java/pdb/symbolserver/HttpSymbolServer.java