Detect stale connections

[cornelk]

reset a timer when a message (ping, etc) gets received, reconnect when no message was send for a specific amount of time.

[dalianzhu]

i found a issue, and not sure how to solve it.

I started a go client and received data，The last few logs are:

[WARNING] Failed to lookup topic map[error:request timed out name:syfjp subscription:nmpc_subscribe_v2_snmpPulsar_system topic:snmp_oceanus_filled_pulsar-partition-3]
[INFO] Reconnecting to broker in 3.2s map[name:syfjp subscription:nmpc_subscribe_v2_snmpPulsar_system topic:snmp_oceanus_filled_pulsar-partition-3]
[WARNING] Failed to lookup topic map[error:request timed out name:syfjp subscription:nmpc_subscribe_v2_snmpPulsar_system topic:snmp_oceanus_filled_pulsar-partition-5]
[WARNING] Detected stale connection to broker map[local_addr:172.19.2.126:34620 remote_addr:pulsar://100.66.21.146:6650]

Then no more messages are received and there is no error log. The program has been stuck for several hours and cannot receive or Ack. Until I restart it.