Kademlia load balancing

[nolash]

in progress

[kortatu]

n * n -> m * n
the ma -> the na

I think it should be.

Suggested change

	* Given `m` requests for no capability and `ma` requests for capability `a` to peers `n` with all capabilities and peers `na` with capability `a`, after `n*n + ma*na` requests the `ma` peers will have made `ma+m` requests each.
	* Given `m` requests for no capability and `ma` requests for capability `a` to peers `n` with all capabilities and peers `na` with capability `a`, after `m*n + ma*na` requests the `na` peers will have made `ma+m` requests each.

[kortatu]

Forwarding issue:
ethersphere/swarm#1656

[kortatu]

What is the definition of a request? Should be accounted each time a peer is returned to the caller or it depends on the use that caller is doing with the Peer.
For example, in Pss, not all peers retrieved with EachConn are used:

p.Kademlia.EachConn(to, addressLength*8, func(sp *network.Peer, po int) bool {
		if po < broadcastThreshold && sent > 0 {
			return false // stop iterating
		}
...

In this case, sp won't be used.
I can see here two possibilities:

1. Each time a peer is used to execute the f function passed to EachConn is accounted as one request.

2. The caller to the load balancing service must signal in some way that a Peer has been used (complicating the API of that service) to be accounted as one request.

[nolash]

Number 2.

A bool argument should suffice, I guess? We can rename the function, then have a new function with the existing name wrap that function, with that argument set so accounting is not done.

[kortatu]

Number 2.

A bool argument should suffice, I guess? We can rename the function, then have a new function with the existing name wrap that function, with that argument set so accounting is not done.

I was implementing something like that, but is a returning value of that f function (now returns two values, one to continue iterating one to signaling that the peer has been used)

[acud]

"returned. This
Hence ... "
can you please reword this?