workbox-streams does not handle opaque responses properly

[jeffposnick]

Library Affected:
workbox-streams

The following code in workbox-streams will break for opaque responses (as well as opaque redirected responses):

workbox/packages/workbox-streams/src/concatenate.ts

Lines 24 to 34 in 9fae132

	function _getReaderFromSource(
	source: StreamSource,
	): ReadableStreamReader<unknown> {
	if (source instanceof Response) {
	return source.body!.getReader();
	}
	if (source instanceof ReadableStream) {
	return source.getReader();
	}
	return new Response(source as BodyInit).body!.getReader();
	}

We shouldn't assume that the response body always exposes getReader().

[jeffposnick]

...actually, I think we just need some logic here to detect whether source.type is 'opaque' or 'opaqueredirect' and log a meaningful error, as there isn't much we can do to combine an opaque body in a non-opaque response stream.