raw

 {raw,
     Protocol :: integer() >= 0,
     OptionNum :: integer() >= 0,
     ValueSpec ::
         (ValueSize :: integer() >= 0) | (ValueBin :: binary())}

1> gen_tcp:listen(8110, [{raw, 65535, 512, <<1:32/native>>}]).
{ok,#Port<0.5>}
2> gen_tcp:listen(8110, [{raw, 65535, 512, <<1:32/native>>}]).
{ok,#Port<0.6>}
3> gen_tcp:listen(8110, [{raw, 65535, 512, <<1:32/native>>}]).
{ok,#Port<0.7>}

so_reuseport =
  case :os.type() do
    {:unix, :linux} -> {:raw, 1, 15, <<1::32-native>>}
    {:unix, :darwin} -> {:raw, 0xffff, 0x0200, <<1::32-native>>}
  end