[clients/avro] Avro IDL example

[OneCricketeer]

AVSC is nice, but JSON is verbose and can be consolidated using Avro IDL (AVDL) syntax.

[ybyzek]

@Cricket007 : what level of adoption do you see of AVSC compared to AVDL? My general understanding is that more customers use AVSC?

[OneCricketeer]

I mostly see AVSC being used in non Java code or when trying to teach people Avro is really just a strongly typed JSON record.

IDL on the other hand allows composition rules (imports), and multiple records can be defined in a single "protocol". This allows a more natural inheritance design rather than heavily nesting and repetitive copying of JSON objects in AVSC definitions.

It works better for comparing to a Thrift & Protobuf knowledge base.

The Maven plugin supports both, so just was going to offer a translation of the existing AVSC code