Fix Missing Batch Size property in ReindexSource while performing Reindexing by ReindexOnServer API

Closes #2145

Author: sumithub

src/Nest/Document/Multiple/ReindexOnServer/ReindexSource.cs

@@ -17,7 +17,10 @@ public interface IReindexSource
 
 		[JsonProperty("type")]
 		Types Type { get; set; }
-	}
+
+        [JsonProperty("size")]
+        int? Size { get; set; }
+    }
 
 	public class ReindexSource : IReindexSource
 	{
@@ -28,16 +31,19 @@ public class ReindexSource : IReindexSource
 		public Indices Index { get; set; }
 
 		public Types Type { get; set; }
-	}
+
+        public int? Size { get; set; }
+    }
 
 	public class ReindexSourceDescriptor : DescriptorBase<ReindexSourceDescriptor, IReindexSource>, IReindexSource
 	{
 		QueryContainer IReindexSource.Query { get; set; }
 		IList<ISort> IReindexSource.Sort { get; set; }
 		Indices IReindexSource.Index { get; set; }
 		Types IReindexSource.Type { get; set; }
+        int? IReindexSource.Size { get; set; }
 
-		public ReindexSourceDescriptor Query<T>(Func<QueryContainerDescriptor<T>, QueryContainer> querySelector) where T : class =>
+        public ReindexSourceDescriptor Query<T>(Func<QueryContainerDescriptor<T>, QueryContainer> querySelector) where T : class =>
 			Assign(a => a.Query = querySelector?.Invoke(new QueryContainerDescriptor<T>()));
 
 		public ReindexSourceDescriptor Sort<T>(Func<SortDescriptor<T>, IPromise<IList<ISort>>> selector) where T : class =>
@@ -47,5 +53,6 @@ public ReindexSourceDescriptor Sort<T>(Func<SortDescriptor<T>, IPromise<IList<IS
 
 		public ReindexSourceDescriptor Type(Types types) => Assign(a => a.Type = types);
 
-	}
+        public ReindexSourceDescriptor Size(int? size) => Assign(a => a.Size = size);
+    }
 }

src/Tests/Document/Multiple/ReindexOnServer/ReindexOnServerApiTests.cs

@@ -54,7 +54,8 @@ protected override LazyResponses ClientUsage() => Calls(
 			.Source(s=>s
 				.Index(CallIsolatedValue)
 				.Type("test")
-				.Query<Test>(q=>q
+                .Size(100)
+                .Query<Test>(q=>q
 					.Match(m=>m
 						.Field(p=>p.Flag)
 						.Query("bar")
@@ -81,9 +82,10 @@ protected override LazyResponses ClientUsage() => Calls(
 				Index = CallIsolatedValue,
 				Type = "test",
 				Query = new MatchQuery { Field = Field<Test>(p=>p.Flag), Query = "bar"},
-				Sort = new List<ISort> { new SortField { Field = "id", Order = SortOrder.Ascending } }
+				Sort = new List<ISort> { new SortField { Field = "id", Order = SortOrder.Ascending } },
+                Size = 100
 
-			},
+            },
 			Destination = new ReindexDestination
 			{
 				Index = CallIsolatedValue + "-clone",
@@ -130,8 +132,9 @@ protected override void ExpectResponse(IReindexOnServerResponse response)
 					index = CallIsolatedValue,
 					query = new { match = new { flag = new { query = "bar" } } },
 					sort = new [] { new { id = new { order = "asc" } } },
-					type = new [] { "test" }
-				}
+					type = new [] { "test" },
+                    size = 100
+                }
 			};
 	}
 }