Add http2 timouts to close bad TCP connection

[wangzlei]

Add http2 timouts to close bad TCP connection

Description:

During ALB maintainance, there could be cases where the TCP connection from Daemon to X-Ray ALB is not properly closed, the Daemon client will not know the TCP connection is no longer working, and will be kept using it for sending new HTTP2 requests as HTTP2 multplexes all the requests in a single TCP connection, this would results in repeated request timeouts and evetually losing data.

In this change 2 timeouts has been added:

• ReadIdleTimeout time.Duration

    ReadIdleTimeout is the timeout after which a health check using ping frame will be carried out if no frame is received on the connection. Note that a ping response will is considered a received frame, so if there is no other traffic on the connection, the health check will be performed every ReadIdleTimeout interval. If zero, no health check is performed.
  

• PingTimeout time.Duration

   PingTimeout is the timeout after which the connection will be closed if a response to Ping is not received. Defaults to 3s (read idle timeout + ping timeout).
  

So in the case of a TCP connection not being closed properly, the http2 transport would detect there is no frame is being received, then send out a Ping, and if no response is received after the PintTimeout, it would close the connection. Existing pending requests would receive an connection error, which would be retried, and subsequent requests would result in a new connection being created.

Link to tracking Issue:

Testing:

Verified the changes in https://github.com/aws/aws-xray-daemon

Documentation:
aws/aws-xray-daemon#216