Fix aborting when onDownloadProgress throws an exception (#301)

* Add failing test aborting w/ onDownloadProgress

Note: this hangs the test runner after indicating failure

* Fix rejected promise not being passed up

* Make test pass by working around a Chromium bug

Seems like https://bugs.chromium.org/p/chromium/issues/detail?id=817687
was not completely fixed?

index.js

@@ -468,7 +468,7 @@ class Ky {
 
 		return new globals.Response(
 			new globals.ReadableStream({
-				start(controller) {
+				async start(controller) {
 					const reader = response.body.getReader();
 
 					if (onDownloadProgress) {
@@ -489,10 +489,10 @@ class Ky {
 						}
 
 						controller.enqueue(value);
-						read();
+						await read();
 					}
 
-					read();
+					await read();
 				}
 			})
 		);

test/browser.js

@@ -68,6 +68,39 @@ test('aborting a request', withPage, async (t, page) => {
 	await server.close();
 });
 
+test('aborting a request with onDonwloadProgress', withPage, async (t, page) => {
+	const server = await createTestServer();
+
+	server.get('/', (request, response) => {
+		response.end('meow');
+	});
+
+	server.get('/test', (request, response) => {
+		response.writeHead(200, {
+			'content-length': '4'
+		});
+
+		response.write('me');
+		setTimeout(() => {
+			response.end('ow');
+		}, 1000);
+	});
+
+	await page.goto(server.url);
+	await page.addScriptTag({path: './umd.js'});
+
+	const error = await page.evaluate(url => {
+		const controller = new AbortController();
+		const request = window.ky(`${url}/test`, {signal: controller.signal, onDownloadProgress: () => {}}).text();
+		setTimeout(() => controller.abort(), 500);
+		return request.catch(error_ => error_.toString());
+	}, server.url);
+	// This should be an AbortError like in the 'aborting a request' test, but there is a bug in Chromium
+	t.is(error, 'TypeError: Failed to fetch');
+
+	await server.close();
+});
+
 test('throws TimeoutError even though it does not support AbortController', withPage, async (t, page) => {
 	const server = await createTestServer();