[whatwg] why does fetch() specify response body processing frequency?

http://fetch.spec.whatwg.org/#fetching says:

Otherwise, if response's body is non-null, run these substeps:

Every 50ms or whenever response's body's is pushed to, whichever is least
frequent and as long as response has no termination reason and end-of-file
has not been pushed, queue a task to process response body for response.

Is this some attempt to reduce overhead on response body processing by
processing larger chunks of data fewer times? If so, it seems like this
should be left up to UA discretion and not specified here. This also
disallows using the response body stream as a low latency channel. For
example, if you were fetching video or audio content (like YouTube does
with XHRs), adding an arbitrary 50ms delay seems undesirable. Also, if you
were running an application layer protocol on top of the request/response
body streams, then the 50 ms delay seems to incur unnecessary latency.

Sorry if I missed some context around this. If there was previous
discussion on this that I should read, please point it out for me. Thanks.

Received on Tuesday, 22 July 2014 21:31:51 UTC