Experimental clone attempt of http://sourceforge.net/projects/afterglow
        each datum is reduced as src -> event -> dst and the data are graphed.
        by default we have IP.src -> IP.dport -> IP.dst

def afterglow(self, src=None, event=None, dst=None, **kargs):
        """Experimental clone attempt of http://sourceforge.net/projects/afterglow
        each datum is reduced as src -> event -> dst and the data are graphed.
        by default we have IP.src -> IP.dport -> IP.dst"""
        if src is None:
            src = lambda x: x['IP'].src
        if event is None:
            event = lambda x: x['IP'].dport
        if dst is None:
            dst = lambda x: x['IP'].dst
        sl = {}
        el = {}
        dl = {}
        for i in self.res:
            try:
                s, e, d = src(i), event(i), dst(i)
                if s in sl:
                    n, lst = sl[s]
                    n += 1
                    if e not in lst:
                        lst.append(e)
                    sl[s] = (n, lst)
                else:
                    sl[s] = (1, [e])
                if e in el:
                    n, lst = el[e]
                    n += 1
                    if d not in lst:
                        lst.append(d)
                    el[e] = (n, lst)
                else:
                    el[e] = (1, [d])
                dl[d] = dl.get(d, 0) + 1
            except Exception:
                continue

        import math

        def normalize(n):
            return 2 + math.log(n) / 4.0

        def minmax(x):
            m, M = reduce(lambda a, b: (min(a[0], b[0]), max(a[1], b[1])),
                          ((a, a) for a in x))
            if m == M:
                m = 0
            if M == 0:
                M = 1
            return m, M

        mins, maxs = minmax(x for x, _ in six.itervalues(sl))
        mine, maxe = minmax(x for x, _ in six.itervalues(el))
        mind, maxd = minmax(six.itervalues(dl))

        gr = 'digraph "afterglow" {\n\tedge [len=2.5];\n'

        gr += "# src nodes\n"
        for s in sl:
            n, _ = sl[s]
            n = 1 + float(n - mins) / (maxs - mins)
            gr += '"src.%s" [label = "%s", shape=box, fillcolor="#FF0000", style=filled, fixedsize=1, height=%.2f,width=%.2f];\n' % (repr(s), repr(s), n, n)  # noqa: E501
        gr += "# event nodes\n"
        for e in el:
            n, _ = el[e]
            n = n = 1 + float(n - mine) / (maxe - mine)
            gr += '"evt.%s" [label = "%s", shape=circle, fillcolor="#00FFFF", style=filled, fixedsize=1, height=%.2f, width=%.2f];\n' % (repr(e), repr(e), n, n)  # noqa: E501
        for d in dl:
            n = dl[d]
            n = n = 1 + float(n - mind) / (maxd - mind)
            gr += '"dst.%s" [label = "%s", shape=triangle, fillcolor="#0000ff", style=filled, fixedsize=1, height=%.2f, width=%.2f];\n' % (repr(d), repr(d), n, n)  # noqa: E501

        gr += "###\n"
        for s in sl:
            n, lst = sl[s]
            for e in lst:
                gr += ' "src.%s" -> "evt.%s";\n' % (repr(s), repr(e))
        for e in el:
            n, lst = el[e]
            for d in lst:
                gr += ' "evt.%s" -> "dst.%s";\n' % (repr(e), repr(d))

        gr += "}"
        return do_graph(gr, **kargs)