[case] subway meet long latency when using quicknode.

[atenjin]

This is the growth curve of requests with a connection time of more than 5 seconds

This is the connection that has not returned.

after we switch the endpoint from quicknode to nodereal, the curve recovers (But it is possible that restarting the proxy restored it.)

https://mainnet-grafana.alt.technology/explore?schemaVersion=1&panes=%7B%22pf0%22:%7B%22datasource%22:%22P4169E866C3094E38%22,%22queries%22:%5B%7B%22refId%22:%22Failed%20Reuqests%22,%22expr%22:%22sum%28subway_rpc_calls_started%7Bjob%3D%5C%22bsc-subway%5C%22%7D%29%20-%20sum%28subway_rpc_calls_finished%7Bjob%3D%5C%22bsc-subway%5C%22%7D%29%22,%22range%22:true,%22instant%22:true,%22datasource%22:%7B%22type%22:%22prometheus%22,%22uid%22:%22P4169E866C3094E38%22%7D,%22editorMode%22:%22code%22,%22legendFormat%22:%22fails%22,%22useBackend%22:false,%22disableTextWrap%22:false,%22fullMetaSearch%22:false,%22includeNullMetadata%22:true,%22format%22:%22time_series%22,%22exemplar%22:false,%22hide%22:false%7D,%7B%22refId%22:%22Timeout%20Requests%20%285s%29%22,%22expr%22:%22sum%28subway_rpc_calls_time_bucket%7Bjob%3D%5C%22bsc-subway%5C%22,%20le%3D%5C%22%2BInf%5C%22%7D%29%20-%20sum%28subway_rpc_calls_time_bucket%7Bjob%3D%5C%22bsc-subway%5C%22,%20le%3D%5C%225%5C%22%7D%29%22,%22range%22:true,%22instant%22:true,%22datasource%22:%7B%22type%22:%22prometheus%22,%22uid%22:%22P4169E866C3094E38%22%7D,%22editorMode%22:%22code%22,%22legendFormat%22:%22timeouts%22,%22hide%22:false%7D%5D,%22range%22:%7B%22from%22:%22now-1h%22,%22to%22:%22now%22%7D%7D%7D&orgId=1

what we plan to do:
@Revolution1

• add the above curve into our dashboard
• add alert for this metrics

@koushiro @yjhmelody

• consider to find which target for the log that we can open for proxy
• consider whether it can be a future to switch between different enpoint