Support batch multiPart requests and responses

sdk/core/Azure.Core/src/HttpHeader.cs

@@ -131,9 +131,19 @@ public static class Names
             /// Returns. <code>"If-Unmodified-Since"</code>
             /// </summary>
             public static string IfUnmodifiedSince => "If-Unmodified-Since";
+            /// <summary>
+            /// Returns. <code>"Referer"</code>
+            /// </summary>
+            public static string Referer => "Referer";
+            /// <summary>
+            /// Returns. <code>"Host"</code>
+            /// </summary>
+            public static string Host => "Host";
 
-            internal static string Referer => "Referer";
-            internal static string Host => "Host";
+            /// <summary>
+            /// Returns <code>"Content-Disposition"</code>
+            /// </summary>
+            public static string ContentDisposition => "Content-Disposition";
         }
 
 #pragma warning disable CA1034 // Nested types should not be visible

sdk/core/Azure.Core/src/RequestContent.cs

@@ -7,6 +7,7 @@
 using System.Threading.Tasks;
 using System.Threading;
 using System.Buffers;
+using System.Collections.Generic;
 
 namespace Azure.Core
 {
@@ -105,7 +106,8 @@ public override void WriteTo(Stream stream, CancellationToken cancellationToken)
                     {
                         cancellationToken.ThrowIfCancellationRequested();
                         var read = _stream.Read(buffer, 0, buffer.Length);
-                        if (read == 0) { break; }
+                        if (read == 0)
+                        { break; }
                         cancellationToken.ThrowIfCancellationRequested();
                         stream.Write(buffer, 0, read);
                     }

sdk/core/Azure.Core/src/Shared/BatchConstants.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+namespace Azure.Core
+{
+    /// <summary>
+    /// Constants used by the batching APIs.
+    /// </summary>
+    internal static class BatchConstants
+    {
+        public const int KB = 1024;
+        public const int NoStatusCode = 0;
+        public const int RequestBufferSize = KB;
+        public const int ResponseLineSize = 4 * KB;
+        public const int ResponseBufferSize = 16 * KB;
+
+        public const string XmsVersionName = "x-ms-version";
+        public const string XmsClientRequestIdName = "x-ms-client-request-id";
+        public const string XmsReturnClientRequestIdName = "x-ms-return-client-request-id";
+        public const string ContentIdName = "Content-ID";
+        public const string ContentLengthName = "Content-Length";
+
+        public const string MultipartContentTypePrefix = "multipart/mixed; boundary=";
+        public const string RequestContentType = "Content-Type: application/http";
+        public const string RequestContentTransferEncoding = "Content-Transfer-Encoding: binary";
+        public const string BatchSeparator = "--";
+        public const string HttpVersion = "HTTP/1.1";
+    }
+}

sdk/core/Azure.Core/src/Shared/BatchErrors.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using Azure.Core.Pipeline;
+
+namespace Azure.Core
+{
+    /// <summary>
+    /// Errors raised by the batching APIs.
+    /// </summary>
+    internal static class BatchErrors
+    {
+        public static InvalidOperationException InvalidBatchContentType(string contentType) =>
+            new InvalidOperationException($"Expected {HttpHeader.Names.ContentType} to start with {BatchConstants.MultipartContentTypePrefix} but received {contentType}");
+
+        public static InvalidOperationException InvalidHttpStatusLine(string statusLine) =>
+            new InvalidOperationException($"Expected an HTTP status line, not {statusLine}");
+
+        public static InvalidOperationException InvalidHttpHeaderLine(string headerLine) =>
+            new InvalidOperationException($"Expected an HTTP header line, not {headerLine}");
+
+        public static RequestFailedException InvalidResponse(ClientDiagnostics clientDiagnostics, Response response, Exception innerException) =>
+            clientDiagnostics.CreateRequestFailedExceptionWithContent(response, message: "Invalid response", innerException: innerException);
+
+    }
+}