Channel should be attached whenever subscribe is called if the channe…

…l is in the @initialized@, @detaching@, or @detached@ states.

textile/features.textile

@@ -675,7 +675,7 @@ h3(#realtime-channel). RealtimeChannel
 * @(RTL7)@ @RealtimeChannel#subscribe@ function:
 ** @(RTL7a)@ Subscribe with a single listener argument subscribes a listener to all messages
 ** @(RTL7b)@ Subscribe with a name argument and a listener argument subscribes a listener to only messages whose @name@ member matches the string name
-** @(RTL7c)@ Implicitly attaches the @RealtimeChannel@ if the channel is in the @INITIALIZED@ state. The optional callback, if provided, is called according to "@RTL4d@":#RTL4d based on the implicit attach operation. The listener will always be registered regardless of the implicit attach result
+** @(RTL7c)@ Implicitly attaches the @RealtimeChannel@ if the channel is in the @INITIALIZED@, @DETACHING@, or @DETACHED@ states. The optional callback, if provided, is called according to "@RTL4d@":#RTL4d based on the implicit attach operation. The listener will always be registered regardless of the implicit attach result
 ** @(RTL7d)@ Messages delivered are automatically decoded based on the @encoding@ attribute; see @RestChannel@ encoding features. Tests should exist to publish and subscribe to encoded messages using the "AES 128":https://github.com/ably/ably-common/blob/main/test-resources/crypto-data-128.json and "AES 256":https://github.com/ably/ably-common/blob/main/test-resources/crypto-data-256.json fixture test data
 ** @(RTL7e)@ If a message cannot be decoded or decrypted successfully, it should be delivered to the listener with the @encoding@ attribute set indicating the residual encoding state, and an error should be logged
 ** @(RTL7f)@ A test should exist ensuring published messages are not echoed back to the subscriber when @echoMessages@ is set to false in the @RealtimeClient@ library constructor