This commit introduces the fact that build.WithGenerateStoreFunc()
needs to be used for configuring properly the `Builder` (like any other
`With...` method.
* rename: `WithCustomGenerateStoreFunc` to `WithGenerateStoreFunc`.
* remove buildStorFunc defaulting in `NewBuilder()` function
* add `DefaultGenerateStoreFunc()` method in `BuilderInterface`
* update `Builder initialisation` in `main.go`
Signed-off-by: cedric lamoriniere <cedric.lamoriniere@datadoghq.com>
* Allow to extend the internal Builder
* All logics still internal
* Add in `metric.Family` the metric family `Type` (counter, gauge)
Signed-off-by: cedric lamoriniere <cedric.lamoriniere@datadoghq.com>