C# Class Akka.Cluster.Gossip

Represents the state of the cluster; cluster ring membership, ring convergence - all versioned by a vector clock. When a node is joining the `Member`, with status `Joining`, is added to `members`. If the joining node was downed it is moved from `overview.unreachable` (status `Down`) to `members` (status `Joining`). It cannot rejoin if not first downed. When convergence is reached the leader change status of `members` from `Joining` to `Up`. When failure detector consider a node as unavailable it will be moved from `members` to `overview.unreachable`. When a node is downed, either manually or automatically, its status is changed to `Down`. It is also removed from `overview.seen` table. The node will reside as `Down` in the `overview.unreachable` set until joining again and it will then go through the normal joining procedure. When a `Gossip` is received the version (vector clock) is used to determine if the received `Gossip` is newer or older than the current local `Gossip`. The received `Gossip` and local `Gossip` is merged in case of conflicting version, i.e. vector clocks without same history. When a node is told by the user to leave the cluster the leader will move it to `Leaving` and then rebalance and repartition the cluster and start hand-off by migrating the actors from the leaving node to the new partitions. Once this process is complete the leader will move the node to the `Exiting` state and once a convergence is complete move the node to `Removed` by removing it from the `members` set and sending a `Removed` command to the removed node telling it to shut itself down.