Document capabilities / best practices / limitations for connect datagen

[kaiwaehner]

There are a lot of example avro files in the resources folder. Though, you still need to take a look at all of them to find out what you can do, and even harder what you cannot do.

You can probably find out limitations in the Avro documentation, though i would like to see a list of examples in the kafka-connect-datagen documentation to show the capabilities - including limitations (e.g. after trying for some time, I learned that you cannot use regex for integer).

If there is a good Avro documentation which fits for this, we should link to it. If not, maybe add some content to this documentation.

@ybyzek @rmoff :-)

[kaiwaehner]

Okay, I see it links to https://github.com/confluentinc/avro-random-generator

=> This should be sufficient.