Discovery service does not support PSUBSCRIBE

[tishun]

Feature Request

When connecting to the Discovery Service the driver attempts to subscribe for topology updates

Is your feature request related to a problem? Please describe

SERVER:8001> PSUBSCRIBE
(error) ERR unknown command

Exception in thread "main" io.lettuce.core.RedisConnectionException: Unable to connect to redis-sentinel://SERVER:8001?sentinelMasterId=MASTERID
	at io.lettuce.core.RedisConnectionException.create(RedisConnectionException.java:78)
	at io.lettuce.core.masterreplica.MasterReplica.getConnection(MasterReplica.java:261)
	at io.lettuce.core.masterreplica.MasterReplica.connect(MasterReplica.java:113)
	at acme.lettuce.SentinelDeployment.main(SentinelDeployment.java:28)
Caused by: io.lettuce.core.RedisException: Cannot attach to Redis Sentinel for topology refresh
	at io.lettuce.core.masterreplica.SentinelTopologyRefreshConnections.onEmit(SentinelTopologyRefreshConnections.java:59)
	Suppressed: The stacktrace has been enhanced by Reactor, refer to additional information below: 
Assembly trace from producer [reactor.core.publisher.MonoCompletionStage] :
	reactor.core.publisher.Mono.fromCompletionStage(Mono.java:543)
	io.lettuce.core.masterreplica.SentinelConnector.initializeConnection(SentinelConnector.java:100)
Error has been observed at the following site(s):
	*__Mono.fromCompletionStage ⇢ at io.lettuce.core.masterreplica.SentinelConnector.initializeConnection(SentinelConnector.java:100)
	|_       Mono.onErrorResume ⇢ at io.lettuce.core.masterreplica.SentinelConnector.initializeConnection(SentinelConnector.java:100)
	*_________________Mono.then ⇢ at io.lettuce.core.masterreplica.ResumeAfter.thenError(ResumeAfter.java:78)
	|_           Mono.doFinally ⇢ at io.lettuce.core.masterreplica.ResumeAfter.thenError(ResumeAfter.java:78)
	*_________________Mono.then ⇢ at io.lettuce.core.masterreplica.SentinelConnector.initializeConnection(SentinelConnector.java:102)
	*______________Mono.flatMap ⇢ at io.lettuce.core.masterreplica.SentinelConnector.connectAsync(SentinelConnector.java:69)
	|_          Mono.onErrorMap ⇢ at io.lettuce.core.masterreplica.SentinelConnector.connectAsync(SentinelConnector.java:76)
Original Stack Trace:
		at io.lettuce.core.masterreplica.SentinelTopologyRefreshConnections.onEmit(SentinelTopologyRefreshConnections.java:59)
		at io.lettuce.core.masterreplica.CompletableEventLatchSupport.emit(CompletableEventLatchSupport.java:120)
		at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
		at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:153)
		at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174)
		at io.netty.util.concurrent.DefaultEventExecutor.run(DefaultEventExecutor.java:66)
		at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
		at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
		at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
		at java.base/java.lang.Thread.run(Thread.java:1583)

Describe the solution you'd like

The driver should handle DiscoveryService connections

[tishun]

See also #1168