Returns information about the active ZeroMQ notifications.
curl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"getzmqnotifications","params":[]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/[
{
"type": "pubhashblock",
"address": "tcp://127.0.0.1:28332",
"hwm": 1000
}
]