Publishes data to a topic
This instruction is the way to communicate with the rest of the actors in the database. It will send a data message to a particular topic, pushing nothing back to the stack. All topic subscribers will receive it.
PumpkinDB> "Hi" "MAIN" PUBLISH
Allocates for sending data copies.
EmptyStack error if stack is less than two items on the stack.
empty_stack : [PUBLISH] TRY UNWRAP 0x04 EQUAL?. empty_stack_1 : [1 PUBLISH] TRY UNWRAP 0x04 EQUAL?.