Function all_nodes_with_value 

pub fn all_nodes_with_value<T, I, F>(
    nodes_items: I,
    f: F,
) -> impl FnMut(ClusterEvent) -> Ready<bool>
where
    T: PartialEq + Eq,
    I: IntoIterator<Item = (RustNodeId, T)>,
    F: FnMut(RustNodeEvent) -> Option<T>,

For an event for a rust node id, that f maps to Some(v), removes the pair (id, v) from the nodes_items, returning true if it runs out.