Created attachment 34261 [details]
Patch to provide rate-initial-burst to rate limit module

We deliver media where the licensing requires we can provide streaming, but not
downloads.  As a part of complying, we use rate limiting so that even if the
user scrapes an underlying mp3 URL, they will still take an hour to download
an hour's worth of content.

One complaint is slow start times for streams to iOS devices.  Measurements
suggest that there is a fixed, 1/2 megabyte initial fetch before any playing
occurs for the user.  Attached is a second parameter for the rate limit
module, rate-initial-burst, which specifies a number K bytes which will
be provided at full speed before throttling back to the configured rate.
With this set to 512, we have had multiple months of satisfactory operation.