Ensure events are buffered when NetworkPeer is not ready

[ryardley]

If a node connects to the evm contracts before the network peer is ready it may create events destined for the peer to peer network that will never be broadcast causing state inconsistencies

A good way to solve this issue is to place an event buffer before the net module until the net module has connected to at least one network peer.

Reproducability:

• connect to evm event source
• delay connection to network
• notice that events are not broadcast.