Nodes and pods metrics (#466)

* Add models for node metrics

* Add models for pod metrics

* Add extension method for node metrics

* Add extension method for pods metrics

* dotnet format

* fix type: use of interface type

* Add metrics sample

* Add tests for node and pod metrics

examples/metrics/Metrics.cs

@@ -0,0 +1,59 @@
+using k8s;
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace metrics
+{
+    class Program
+    {
+        static async Task NodesMetrics(IKubernetes client)
+        {
+            var nodesMetrics = await client.GetKubernetesNodesMetricsAsync().ConfigureAwait(false);
+
+            foreach (var item in nodesMetrics.Items)
+            {
+                Console.WriteLine(item.Metadata.Name);
+
+                foreach (var metric in item.Usage)
+                {
+                    Console.WriteLine($"{metric.Key}: {metric.Value}");
+                }
+            }
+        }
+
+        static async Task PodsMetrics(IKubernetes client)
+        {
+            var podsMetrics = await client.GetKubernetesPodsMetricsAsync().ConfigureAwait(false);
+
+            if (!podsMetrics.Items.Any())
+            {
+                Console.WriteLine("Empty");
+            }
+
+            foreach (var item in podsMetrics.Items)
+            {
+                foreach (var container in item.Containers)
+                {
+                    Console.WriteLine(container.Name);
+
+                    foreach (var metric in container.Usage)
+                    {
+                        Console.WriteLine($"{metric.Key}: {metric.Value}");
+                    }
+                }
+                Console.Write(Environment.NewLine);
+            }
+        }
+
+        static async Task Main(string[] args)
+        {
+            var config = KubernetesClientConfiguration.BuildConfigFromConfigFile();
+            var client = new Kubernetes(config);
+
+            await NodesMetrics(client).ConfigureAwait(false);
+            Console.WriteLine(Environment.NewLine);
+            await PodsMetrics(client).ConfigureAwait(false);
+        }
+    }
+}

examples/metrics/metrics.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\KubernetesClient\KubernetesClient.csproj" />
+  </ItemGroup>
+
+
+</Project>