to make goreportcard a bit happier
https://goreportcard.com/report/github.com/docker/docker
also found that `TestCpToErrDstParentNotExists()` was
partially broken, because a `runDockerCp()` was inadvertently
removed in f26a31e80c
`TestDaemonRestartSaveContainerExitCode()` didn't verify
the actual _Error_ message, so added that to the test,
and updated the test to take into account that the
"experimental" CI enables `--init` on containers.
`TestVolumeCLICreateOptionConflict()` only checked
for an error to occur, but didn't validate if the
error was due to conflicting options.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Creates a `fixedBuffer` type that is used to encapsulate functionality
for reading/writing from the underlying byte slices.
Uses lazily-loaded set of sync.Pools for storing buffers that are no
longer needed so they can be re-used.
```
benchmark old ns/op new ns/op delta
BenchmarkBytesPipeWrite-8 138469 48985 -64.62%
BenchmarkBytesPipeRead-8 130922 56601 -56.77%
benchmark old allocs new allocs delta
BenchmarkBytesPipeWrite-8 18 8 -55.56%
BenchmarkBytesPipeRead-8 0 0 +0.00%
benchmark old bytes new bytes delta
BenchmarkBytesPipeWrite-8 66903 1649 -97.54%
BenchmarkBytesPipeRead-8 0 1 +Inf%
```
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
