Hi,
Please see below the publishmulti syntax.
publishmulti stream1 '[{"keys":["11111-11111","20180101","MC2"],"data":{"json":{"name":"Item1","dob":"01012019"}}},{"keys":["22222-22222","20180102","MC2"],"data":{"json":{"name":"Item2","dob":"02012019"}}}]'
Thanks.