Observable req/res

[mantycore]

• When req is send, add to the waiting Map an object with a list of all nodes to which te message was sent
• Rebroadcasts are not supported, instead nodes exchange the information about peers on pings? Study peer-relay protocol
• If rebroadcasts are to be supported, rebroadcasting node needs to send list of node it rebroadcasts to to the origin of the message to be stored kn the object
• When res is received, the node that responded is marked in the object, and Observable event is emited
• When all nodes in the object are marked, the observable is completed
• The observable fails on timeout (or maybe on any/all res being error messages?)

[mantycore]

Implemented (but without exchanging information on peers, which is probably a separate task).