cmd/dist: copy trailing text more directly in testJSONFilter.process
Use io.Copy¹ that matches the comment more closely, avoids the
possibility of needing a bigger array, and is slightly shorter.
Its downside is that it takes two w.Write calls instead of one.
¹ Admittedly, it was temping to use io.CopyBuffer since the 'data'
byte slice becomes a viable buffer after its contents are written.
I resisted that temptation for two reasons.
One, it would need the io.Reader returned by dec.Buffered() (currently
a *bytes.Reader) to not implement the io.WriterTo interface for any
chance of making a positive difference. This seems not very likely.
Two, to avoid burdening anyone with determining that io.CopyBuffer
won't panic without 'if len(data) == 0 && data != nil { data = nil }'
because json.Marshal never returns an empty but non-nil byte slice.
Change-Id: I33c53d9d990f6ee79cd3ab90f12e3b575b9ebe72
Reviewed-on: https://go-review.googlesource.com/c/go/+/497736 Reviewed-by: Austin Clements <austin@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Bypass: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>