Enum Event 

pub enum Event {
    Post(Val, Val),
    Link(ConnId, Sender<Frame>),
    Down(ConnId),
    Node(ConnId, Val),
    Gone(String),
}

One queue carries everything arriving from outside the heap, so a quiescent node waits on a single receiver rather than selecting over a set that changes as peers come and go.

Variants

Post(Val, Val)

Link(ConnId, Sender<Frame>)

A connection established while the loop runs, which is every one a node accepts rather than makes; the counterpart before it starts is World::link.

Down(ConnId)

The only liveness edge a node has about a far side.

Node(ConnId, Val)

A frame addressed to the node rather than a task in it (crate::link::NODE):

('watch id)         watch a task of yours for me
('down  id result)  it ended, and this is what with

Not a service reached through the greeter, because a table held by a task is lost when the task restarts with no event to say so.

Gone(String)

A host peer’s adapter has dropped the receiving end. Raised by a waiter the loop spawns, so a peer ending is an edge rather than a question.