Basic net attributes for tcp and udp input operators

[sumo-drosiek]

I would like to add basic net attributes (resources?) to the entries from tcp and udp input operators.

For start i was thinking about

     -> net.transport: STRING(IP.TCP)
     -> net.peer.ip: STRING(127.0.0.1)
     -> net.peer.port: STRING(35278)
     -> net.host.ip: STRING(127.0.0.1)
     -> net.host.port: STRING(54526)

I would like to add it behind add_attributes configuration option

Any thoughts on that? Any objections?