[ZOOKEEPER-3847] Add a couple metrics to help track Netty memory usage

• Type: Sub-task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.6.2
• Component/s: metric system
• Assignee: Jie Huang
• Reporter: Jie Huang
• Created: 22/May/20 17:33
• Updated: 10/Sep/20 10:43
• Resolved: 28/May/20 03:45

Description

Adding these metrics:

• RESPONSE_BYTES: size of responses (in bytes) being sent to a client
• WATCH_BYTES: size of watch events (in bytes) being sent to a client