Move resumability decisions from the client to the server

build/data/versions.yaml

@@ -1,2 +1,2 @@
-specification: "6.0.0"
+specification: "6.1.0"
 protocol: 6

specifications/api-docstrings.md

@@ -474,7 +474,7 @@ Describes the possible states of a [`RestChannel`]{@link RestChannel} or [`Realt
 | ATTACHED || The attach has succeeded. In the `ATTACHED` state a client may publish and subscribe to messages, or be present on the channel. |
 | DETACHING || A detach has been initiated on an `ATTACHED` channel by sending a request to Ably. This is a transient state, followed either by a transition to `DETACHED` or `FAILED`. |
 | DETACHED || The channel, having previously been `ATTACHED`, has been detached by the user. |
-| SUSPENDED || The channel, having previously been `ATTACHED`, has lost continuity, usually due to the client being disconnected from Ably for longer than two minutes. It will automatically attempt to reattach as soon as connectivity is restored. |
+| SUSPENDED || The channel, having previously been `ATTACHED`, is waiting for the client to reconnect to Ably after an extended period of disconnection. It will automatically reattach once connectivity is restored. Message continuity may have been lost, but the authoritative source for this is the [`resumed`]{@link ChannelStateChange#resumed}) flag on the subsequent `attached` state change. |
 | FAILED || An indefinite failure condition. This state is entered if a channel error has been received from the Ably service, such as an attempt to attach without the necessary access rights. |
 
 ## enum ChannelEvent
@@ -977,8 +977,8 @@ Describes the realtime [`Connection`]{@link Connection} object states.
 | INITIALIZED || A connection with this state has been initialized but no connection has yet been attempted. |
 | CONNECTING || A connection attempt has been initiated. The connecting state is entered as soon as the library has completed initialization, and is reentered each time connection is re-attempted following disconnection. |
 | CONNECTED || A connection exists and is active. |
-| DISCONNECTED || A temporary failure condition. No current connection exists because there is no network connectivity or no host is available. The disconnected state is entered if an established connection is dropped, or if a connection attempt was unsuccessful. In the disconnected state the library will periodically attempt to open a new connection (approximately every 15 seconds), anticipating that the connection will be re-established soon and thus connection and channel continuity will be possible. In this state, developers can continue to publish messages as they are automatically placed in a local queue, to be sent as soon as a connection is reestablished. Messages published by other clients while this client is disconnected will be delivered to it upon reconnection, so long as the connection was resumed within 2 minutes. After 2 minutes have elapsed, recovery is no longer possible and the connection will move to the `SUSPENDED` state. |
-| SUSPENDED || A long term failure condition. No current connection exists because there is no network connectivity or no host is available. The suspended state is entered after a failed connection attempt if there has then been no connection for a period of two minutes. In the suspended state, the library will periodically attempt to open a new connection every 30 seconds. Developers are unable to publish messages in this state. A new connection attempt can also be triggered by an explicit call to [`connect()`]{@link Connection#connect}. Once the connection has been re-established, channels will be automatically re-attached. The client has been disconnected for too long for them to resume from where they left off, so if it wants to catch up on messages published by other clients while it was disconnected, it needs to use the [History API](https://ably.com/docs/realtime/history). |
+| DISCONNECTED || A temporary failure condition. The client has been disconnected from Ably, usually due to network connectivity. It will periodically attempt to open a new connection (about every 15 seconds). In this state, you can continue to publish messages, which will be queued to be sent once a connection is reestablished. Messages published by other clients while this client is disconnected will be delivered to it upon reconnection if the server is able to preserve continuity. |
+| SUSPENDED || A long term failure condition. A client moves to this state once it has been in the `disconnected` state for over two minutes. Developers are unable to publish messages in this state, and any queued messages are discarded. The library will attempt to reconnect every 30 seconds; an attempt can also be triggered by calling [`connect()`]{@link Connection#connect}. |
 | CLOSING || An explicit request by the developer to close the connection has been sent to the Ably service. If a reply is not received from Ably within a short period of time, the connection is forcibly terminated and the connection state becomes `CLOSED`. |
 | CLOSED || The connection has been explicitly closed by the client. In the closed state, no reconnection attempts are made automatically by the library, and clients may not publish messages. No connection state is preserved by the service or by the library. A new connection attempt can be triggered by an explicit call to [`connect()`]{@link Connection#connect}, which results in a new connection. |
 | FAILED || This state is entered if the client library encounters a failure condition that it cannot recover from. This may be a fatal connection error received from the Ably service, for example an attempt to connect with an incorrect API key, or a local terminal error, for example the token in use has expired and the library does not have any way to renew it. In the failed state, no reconnection attempts are made automatically by the library, and clients may not publish messages. A new connection attempt can be triggered by an explicit call to [`connect()`]{@link Connection#connect}. |