Solr does not have a binary request/response format which can be supported by any client/programming language. The JavaBin format is Java only and is also not standards based.
The proposal (spinoff from
SOLR-1535 and SOLR-2204) is to investigate creation of an Apache Avro based serialization format. First goal is to produce Avro Schemas for Request and Response and then provide AvroRequestHandler and AvroResponseWriter. Secondary goal is to use it for replication.