[WIP] Remove ToArray calls on MemoryStream

src/Elasticsearch.Net/Extensions/UtilExtensions.cs

@@ -27,6 +27,16 @@ internal static string Utf8String(this MemoryStream ms)
 
 			return Encoding.UTF8.GetString(buffer.Array, buffer.Offset, buffer.Count);
 		}
+		/// <summary> Attempts to return to underlying bytes buffer (no-copy) if possible </summary>
+		internal static byte[] ToArrayOrBuffer(this MemoryStream ms)
+		{
+			if (ms is null) return null;
+
+			if (!ms.TryGetBuffer(out var buffer) || buffer.Array is null)
+				return ms.ToArray();
+
+			return buffer.Array;
+		}
 
 		internal static byte[] Utf8Bytes(this string s) => s.IsNullOrEmpty() ? null : Encoding.UTF8.GetBytes(s);
 

src/Elasticsearch.Net/Serialization/ElasticsearchSerializerExtensions.cs

@@ -1,5 +1,4 @@
 using Elasticsearch.Net.Extensions;
-using Elasticsearch.Net.Utf8Json;
 
 namespace Elasticsearch.Net
 {
@@ -16,7 +15,7 @@ public static byte[] SerializeToBytes<T>(
 			using (var ms = memoryStreamFactory.Create())
 			{
 				serializer.Serialize(data, ms, formatting);
-				return ms.ToArray();
+				return ms.ToArrayOrBuffer();
 			}
 		}
 

src/Elasticsearch.Net/Transport/Pipeline/ResponseBuilder.cs

@@ -174,7 +174,7 @@ private static bool NeedsToEagerReadStream<TResponse>()
 
 		private static byte[] SwapStreams(ref Stream responseStream, ref MemoryStream ms)
 		{
-			var bytes = ms.ToArray();
+			var bytes = ms.ToArrayOrBuffer();
 			responseStream.Dispose();
 			responseStream = ms;
 			responseStream.Position = 0;

src/Elasticsearch.Net/Transport/PostData.cs

@@ -124,7 +124,7 @@ public override void Write(Stream writableStream, IConnectionConfigurationValues
 				ms.CopyTo(writableStream, BufferSize);
 			}
 			if (Type != 0)
-				WrittenBytes = ms?.ToArray();
+				WrittenBytes = ms?.ToArrayOrBuffer();
 		}
 
 		public override async Task WriteAsync(Stream writableStream, IConnectionConfigurationValues settings, CancellationToken cancellationToken)
@@ -169,7 +169,7 @@ await settings.RequestResponseSerializer.SerializeAsync(o, stream, Serialization
 				await ms.CopyToAsync(writableStream, BufferSize, cancellationToken).ConfigureAwait(false);
 			}
 			if (Type != 0)
-				WrittenBytes = ms?.ToArray();
+				WrittenBytes = ms?.ToArrayOrBuffer();
 		}
 	}
 }

src/Elasticsearch.Net/Transport/SerializableData.cs

@@ -1,6 +1,7 @@
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
+using Elasticsearch.Net.Extensions;
 
 namespace Elasticsearch.Net
 {
@@ -31,7 +32,7 @@ public override void Write(Stream writableStream, IConnectionConfigurationValues
 				ms.CopyTo(writableStream, BufferSize);
 			}
 			if (Type != 0)
-				WrittenBytes = ms?.ToArray();
+				WrittenBytes = ms?.ToArrayOrBuffer();
 		}
 
 		public static implicit operator SerializableData<T>(T serializableData) => new SerializableData<T>(serializableData);
@@ -53,7 +54,7 @@ public override async Task WriteAsync(Stream writableStream, IConnectionConfigur
 				await ms.CopyToAsync(writableStream, BufferSize, cancellationToken).ConfigureAwait(false);
 			}
 			if (Type != 0)
-				WrittenBytes = ms?.ToArray();
+				WrittenBytes = ms?.ToArrayOrBuffer();
 		}
 	}
 }

src/Elasticsearch.Net/Utf8Json/Internal/BinaryUtil.cs

@@ -112,9 +112,8 @@ public static
             byte[] FastCloneWithResize(byte[] src, int newSize)
         {
             if (newSize < 0) throw new ArgumentOutOfRangeException("newSize");
-            if (src.Length < newSize) throw new ArgumentException("length < newSize");
-
             if (src == null) return new byte[newSize];
+            if (src.Length < newSize) throw new ArgumentException("length < newSize");
 
             byte[] dst = new byte[newSize];
 

src/Nest/Cat/CatHelpResponseBuilder.cs

@@ -3,6 +3,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Elasticsearch.Net;
+using Elasticsearch.Net.Extensions;
 
 namespace Nest
 {
@@ -20,7 +21,7 @@ public override object DeserializeResponse(IElasticsearchSerializer builtInSeria
 			using (var ms = response.ConnectionConfiguration.MemoryStreamFactory.Create())
 			{
 				stream.CopyTo(ms);
-				var body = ms.ToArray().Utf8String();
+				var body = ms.Utf8String();
 				Parse(catResponse, body);
 			}
 
@@ -46,7 +47,7 @@ public override async Task<object> DeserializeResponseAsync(IElasticsearchSerial
 			using (var ms = response.ConnectionConfiguration.MemoryStreamFactory.Create())
 			{
 				await stream.CopyToAsync(ms, 81920, ctx);
-				var body = ms.ToArray().Utf8String();
+				var body = ms.Utf8String();
 				Parse(catResponse, body);
 			}
 

src/Nest/CommonAbstractions/Extensions/Extensions.cs

@@ -2,6 +2,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Runtime.Serialization;
@@ -96,7 +97,6 @@ internal static string ToEnumValue<T>(this T enumValue) where T : struct
 
 			return null;
 		}
-
 		internal static string Utf8String(this ref ArraySegment<byte> segment) =>
 			StringEncoding.UTF8.GetString(segment.Array, segment.Offset, segment.Count);
 
@@ -161,7 +161,7 @@ internal static bool IsEmpty<T>(this IEnumerable<T> list)
 			return !enumerable.Any() || enumerable.All(t => t == null);
 		}
 
-		internal static void ThrowIfNull<T>(this T value, string name, string message = null) 
+		internal static void ThrowIfNull<T>(this T value, string name, string message = null)
 		{
 			if (value == null && message.IsNullOrEmpty()) throw new ArgumentNullException(name);
 			else if (value == null) throw new ArgumentNullException(name, "Argument can not be null when " + message);

src/Nest/CommonAbstractions/SerializationBehavior/JsonFormatters/ProxyRequestFormatterBase.cs

@@ -1,5 +1,6 @@
 using System.Reflection;
 using Elasticsearch.Net;
+using Elasticsearch.Net.Extensions;
 using Elasticsearch.Net.Utf8Json;
 
 namespace Nest
@@ -41,7 +42,7 @@ public void Serialize(ref JsonWriter writer, TRequestInterface value, IJsonForma
 			using (var ms = settings.MemoryStreamFactory.Create())
 			{
 				untypedDocumentRequest.WriteJson(serializer, ms, SerializationFormatting.None);
-				var v = ms.ToArray();
+				var v = ms.ToArrayOrBuffer();
 				writer.WriteRaw(v);
 			}
 		}

src/Nest/CommonAbstractions/SerializationBehavior/JsonFormatters/SourceFormatter.cs

@@ -1,4 +1,5 @@
 using Elasticsearch.Net;
+using Elasticsearch.Net.Extensions;
 using Elasticsearch.Net.Utf8Json;
 
 namespace Nest
@@ -43,7 +44,7 @@ public virtual void Serialize(ref JsonWriter writer, T value, IJsonFormatterReso
 			{
 				sourceSerializer.Serialize(value, ms, f);
 				// TODO: read each byte instead of creating and allocating an array
-				bytes = ms.ToArray();
+				bytes = ms.ToArrayOrBuffer();
 			}
 
 			writer.WriteRaw(bytes);