ENT-12832: metrics from flows (#7942)

Add ability to register metrics inside flows;

node-api/build.gradle

@@ -70,6 +70,8 @@ dependencies {
     testImplementation "org.junit.jupiter:junit-jupiter-api:${junit_jupiter_version}"
     testImplementation "junit:junit:$junit_version"
 
+    testImplementation "io.dropwizard.metrics:metrics-jmx:$metrics_version"
+
     testRuntimeOnly "org.junit.vintage:junit-vintage-engine:${junit_vintage_version}"
     testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:${junit_jupiter_version}"
     testRuntimeOnly "org.junit.platform:junit-platform-launcher:${junit_platform_version}"

node-api/src/test/kotlin/net/corda/nodeapi/internal/serialization/kryo/KryoCheckpointTest.kt

@@ -1,8 +1,11 @@
 package net.corda.nodeapi.internal.serialization.kryo
 
+import com.codahale.metrics.MetricRegistry
+import com.esotericsoftware.kryo.KryoException
 import org.junit.Ignore
 import org.junit.Test
 import org.junit.jupiter.api.assertDoesNotThrow
+import org.junit.jupiter.api.assertThrows
 import java.util.LinkedList
 import kotlin.test.assertEquals
 
@@ -168,4 +171,15 @@ class KryoCheckpointTest {
         }
         assertEquals(testSize, result)
     }
+
+    /**
+     * This test just ensures that the checkpoints still work in light of [LinkedListItrSerializer].
+     */
+    @Test(timeout=300_000)
+    fun `MetricRegistry cannot checkpoint without error`() {
+        val metricRegistry = MetricRegistry()
+        assertThrows<KryoException>("Class com.codahale.metrics.MetricRegistry is not annotated or on the whitelist, so cannot be used in serialization") {
+            KryoCheckpointSerializer.deserialize(KryoCheckpointSerializer.serialize(metricRegistry, KRYO_CHECKPOINT_CONTEXT), MetricRegistry::class.java, KRYO_CHECKPOINT_CONTEXT)
+        }
+    }
 }