The kafka module use printf-like message to print statistics in rpc_kafka_stats() which doesn't follow the style for other RPC commands that produce data structures parsable as data, like when using jsonrpc.

``` if (rpc->rpl_printf(ctx, "Total messages: %" PRIu64 " Errors: %" PRIu64, msg_total, msg_error) < 0) { rpc->fault(ctx, 500, "Internal error showing total statistics"); return; } ``` I think this is a bug, but easy to fix.