changes to support specific run service URL (#2158)

* changes to support run service url

* feedback

src/Sdk/DTWebApi/WebApi/RunServiceHttpClient.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using GitHub.Services.Common;
+using GitHub.Services.OAuth;
+using GitHub.Services.WebApi;
+using Sdk.WebApi.WebApi;
+
+namespace GitHub.DistributedTask.WebApi
+{
+    [ResourceArea(TaskResourceIds.AreaId)]
+    public class RunServiceHttpClient : RawHttpClientBase
+    {
+        public RunServiceHttpClient(
+            Uri baseUrl,
+            VssOAuthCredential credentials)
+            : base(baseUrl, credentials)
+        {
+        }
+
+        public RunServiceHttpClient(
+            Uri baseUrl,
+            VssOAuthCredential credentials,
+            RawClientHttpRequestSettings settings)
+            : base(baseUrl, credentials, settings)
+        {
+        }
+
+        public RunServiceHttpClient(
+            Uri baseUrl,
+            VssOAuthCredential credentials,
+            params DelegatingHandler[] handlers)
+            : base(baseUrl, credentials, handlers)
+        {
+        }
+
+        public RunServiceHttpClient(
+            Uri baseUrl,
+            VssOAuthCredential credentials,
+            RawClientHttpRequestSettings settings,
+            params DelegatingHandler[] handlers)
+            : base(baseUrl, credentials, settings, handlers)
+        {
+        }
+
+        public RunServiceHttpClient(
+            Uri baseUrl,
+            HttpMessageHandler pipeline,
+            Boolean disposeHandler)
+            : base(baseUrl, pipeline, disposeHandler)
+        {
+        }
+
+        public Task<Pipelines.AgentJobRequestMessage> GetJobMessageAsync(
+            Uri requestUri,
+            string messageId,
+            CancellationToken cancellationToken = default)
+        {
+            HttpMethod httpMethod = new HttpMethod("POST");
+            var payload = new {
+                StreamID = messageId
+            };
+
+            var payloadJson = JsonUtility.ToString(payload);
+            var requestContent = new StringContent(payloadJson, System.Text.Encoding.UTF8, "application/json");
+            return SendAsync<Pipelines.AgentJobRequestMessage>(
+                httpMethod,
+                additionalHeaders: null,
+                requestUri: requestUri,
+                content: requestContent,
+                cancellationToken: cancellationToken);
+        }
+    }
+}