Add code comments

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

Author: sczyh30

pom.xml

@@ -104,18 +104,19 @@
             <version>${javax.annotation-api.version}</version>
         </dependency>
 
+        <!-- reuse a few xDS proto here -->
+        <dependency>
+            <groupId>io.envoyproxy.controlplane</groupId>
+            <artifactId>api</artifactId>
+            <version>${envoy-api.version}</version>
+        </dependency>
+
         <!-- test-scope dependencies -->
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <scope>test</scope>
         </dependency>
-
-        <dependency>
-            <groupId>io.envoyproxy.controlplane</groupId>
-            <artifactId>api</artifactId>
-            <version>${envoy-api.version}</version>
-        </dependency>
     </dependencies>
 
     <dependencyManagement>

src/main/java/io/opensergo/OpenSergoConfigKindRegistry.java

@@ -38,11 +38,15 @@ public final class OpenSergoConfigKindRegistry {
     static {
         KIND_MAP = new ConcurrentHashMap<>();
 
+        // domain: fault-tolerance
         registerConfigKind(ConfigKind.FAULT_TOLERANCE_RULE, FaultToleranceRule.class);
         registerConfigKind(ConfigKind.RATE_LIMIT_STRATEGY, RateLimitStrategy.class);
         registerConfigKind(ConfigKind.THROTTLING_STRATEGY, ThrottlingStrategy.class);
         registerConfigKind(ConfigKind.CONCURRENCY_LIMIT_STRATEGY, ConcurrencyLimitStrategy.class);
         registerConfigKind(ConfigKind.CIRCUIT_BREAKER_STRATEGY, CircuitBreakerStrategy.class);
+
+        // domain: traffic
+        // NOTE: here we've reused a few parts of xDS proto (e.g. route proto)
         registerConfigKind(ConfigKind.TRAFFIC_ROUTER_STRATEGY, RouteConfiguration.class);
     }