…s set (#3478)

…h endpoints

)

w.pr cannot be used to indicate that the pipe has been closed. The problem with
using w.pr is that a write to it in the goroutine launched by writer.open can
race with a read on w.pr in Close.

We just don't write to w.pr in writer.open. The read end of the pipe can still be
closed twice, but that's fine.

…tive for AZURE_STORAGE_CONNECTION_STRING (#3483)

…, "accelerate" (#3486)

…9. (#3487)

…3494)

Issuing many S3 uploads in quick succession causes the following
error:

operation error S3: PutObject, failed to get rate limit token, retry quota exceeded, 0 available, 5 requested

By default, this rate limit is disabled to restore the same behavior
as SDK v1. If `rate_limiter_capacity` is set, then client-side rate
limits will take effect.

Closes #3496