peakMemoryUsage and executionTime explain stats (#497)

Author: rashtao

src/main/java/com/arangodb/entity/AqlExecutionExplainEntity.java

@@ -252,6 +252,8 @@ public static class ExecutionStats {
         private Integer rulesExecuted;
         private Integer rulesSkipped;
         private Integer plansCreated;
+        private Long peakMemoryUsage;
+        private Double executionTime;
 
         public Integer getRulesExecuted() {
             return rulesExecuted;
@@ -265,6 +267,13 @@ public Integer getPlansCreated() {
             return plansCreated;
         }
 
+        public Long getPeakMemoryUsage() {
+            return peakMemoryUsage;
+        }
+
+        public Double getExecutionTime() {
+            return executionTime;
+        }
     }
 
     private ExecutionPlan plan;

src/test/java/com/arangodb/ArangoDatabaseTest.java

@@ -1009,6 +1009,10 @@ void explainQuery(ArangoDatabase db) {
         assertThat(plan.getEstimatedNrItems()).isPositive();
         assertThat(plan.getVariables()).hasSize(2);
         assertThat(plan.getNodes()).isNotEmpty();
+        if (isAtLeastVersion(3, 10)) {
+            assertThat(explain.getStats().getPeakMemoryUsage()).isNotNull();
+            assertThat(explain.getStats().getExecutionTime()).isNotNull();
+        }
     }
 
     @ParameterizedTest(name = "{index}")