this is for supporting external plugins.
external plugins will depend on a few telegraf interface types, as well
as a common telegraf registry.
this will allow external and internal plugins to both share this package
and make it easier to vendor/version the whole thing semantically, which
will make it easier to keep plugins supported across build and telegraf
versions.
see #1717
main reasons behind this:
- make adding/removing tags cheap
- make adding/removing fields cheap
- make parsing cheaper
- make parse -> decorate -> write out bytes metric flow much faster
Refactor serializer to use byte buffer