The appendInt function previously performed a double pass
over the formatted integer. We can avoid the second pass
if we knew the exact length of formatted integer,
allowing us to directly serialize into the output buffer.
Rename formatNano to appendNano to be consistent with
other append-like functionality.
Performance:
name old time/op new time/op delta
FormatRFC3339Nano 109ns ± 1% 72ns ± 1% -34.06% (p=0.000 n=10+10)
Change-Id: Id48f77eb4976fb1dcd6e27fb6a02d29cbf0c026a
Reviewed-on: https://go-review.googlesource.com/c/go/+/444278
Run-TryBot: Joseph Tsai <joetsai@digital-static.net>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: David Chase <drchase@google.com>