* Add additional controller implementations
* remove additional interface
* Fix comparison checks and mark unused contexts
* Switch to time.Now().UTC()
* Add a pointer helper for shadowing loop variables
* Extract anonymous functions for readability
* clean up logging
* Add Type to the Condition proto
* Update some comments and add additional space for readability
* Address PR feedback
* Fix up dirty checks and change to pointer receiver
Replaces the reflection-based implementation of proxycfg's
ConfigSnapshot.Clone with code generated by deep-copy.
While load testing server-based xDS (for consul-dataplane) we discovered
this method is extremely expensive. The ConfigSnapshot struct, directly
or indirectly, contains a copy of many of the structs in the agent/structs
package, which creates a large graph for copystructure.Copy to traverse
at runtime, on every proxy reconfiguration.
