Epidemic peer should be able to send payload to another peer

[poonai]

Is your feature request related to a problem? Please describe.
Right now, the peer knows only how many peers are alive and dead. But, there is no way to get details of the peer. So, we should support a way to send a message to the peer.

My use-case:
My peer listening on two ports. One is by the epidemic and another one is grpc server. All my application logic is on the grpc server. So, I need a way to communicate with my peers to get the information that I want.

How this feature helps me?

As soon I get an alive event, I'll ask for the required details which I want. Then the receiver peer will respond to my question.

Describe the solution you'd like
I need cluster.send_payload method which takes destination peer id and payload as a parameter and sends the payload to the destination peer.

[vertexclique]

Closed by #8