lwIP Stats after one request that was fulfilled very fast:

LINK
        xmit: 57
        rexmit: 0
        recv: 120
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 0

ETHARP
        xmit: 0
        rexmit: 0
        recv: 1
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 115

IP_FRAG
        xmit: 0
        rexmit: 0
        recv: 0
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 0

IP
        xmit: 56
        rexmit: 0
        recv: 59
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 0

ICMP
        xmit: 0
        rexmit: 0
        recv: 0
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 0

IGMP
        lenerr: 0
        chkerr: 0
        v1_rxed: 0
        join_sent: 0
        leave_sent: 0
        unicast_query: 0
        report_sent: 0
        report_rxed: 0
        group_query_rxed: 0

UDP
        xmit: 0
        rexmit: 0
        recv: 0
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 0

TCP
        xmit: 44
        rexmit: 0
        recv: 59
        fw: 0
        drop: 0
        chkerr: 0
        lenerr: 0
        memerr: 0
        rterr: 0
        proterr: 0
        opterr: 0
        err: 0
        cachehit: 0

MEM HEAP
        avail: 0
        used: 0
        max: 0
        err: 0

MEM RAW_PCB
        avail: 4
        used: 0
        max: 0
        err: 0

MEM UDP_PCB
        avail: 4
        used: 0
        max: 0
        err: 0

MEM TCP_PCB
        avail: 6
        used: 0
        max: 3
        err: 0

MEM TCP_PCB_LISTEN
        avail: 8
        used: 1
        max: 1
        err: 0

MEM TCP_SEG
        avail: 32
        used: 0
        max: 8
        err: 0

MEM REASSDATA
        avail: 5
        used: 0
        max: 0
        err: 0

MEM NETBUF
        avail: 8
        used: 0
        max: 1
        err: 0

MEM NETCONN
        avail: 16
        used: 1
        max: 3
        err: 0

MEM TCPIP_MSG_API
        avail: 16
        used: 0
        max: 0
        err: 0

MEM TCPIP_MSG_INPKT
        avail: 8
        used: 0
        max: 7
        err: 0

MEM ARP_QUEUE
        avail: 30
        used: 0
        max: 0
        err: 0

MEM IGMP_GROUP
        avail: 8
        used: 0
        max: 0
        err: 0

MEM SYS_TIMEOUT
        avail: 20
        used: 5
        max: 6
        err: 0

MEM PBUF_REF/ROM
        avail: 40
        used: 0
        max: 0
        err: 0

MEM PBUF_POOL
        avail: 16
        used: 0
        max: 7
        err: 0