Returns details on the active state of the TX memory pool.
curl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"getmempoolinfo","params":[]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/{
"loaded": true,
"size": 12345,
"bytes": 8765432,
"usage": 34567890,
"total_fee": 1.23456789,
"maxmempool": 300000000,
"mempoolminfee": 0.00001000,
"minrelaytxfee": 0.00001000
}