Mark IsValid obsolete for get and delete responses to warn about the behavioral change in #2367 (#2678)

Author: gmarz

src/Nest/Document/Single/Delete/DeleteResponse.cs

@@ -1,4 +1,5 @@
-using Newtonsoft.Json;
+using System;
+using Newtonsoft.Json;
 
 namespace Nest
 {
@@ -40,14 +41,19 @@ public class DeleteResponse : ResponseBase, IDeleteResponse
 
 		[JsonProperty("_type")]
 		public string Type { get; internal set; }
-		
+
 		[JsonProperty("_id")]
 		public string Id { get; internal set; }
-		
+
 		[JsonProperty("_version")]
 		public string Version { get; internal set; }
-		
+
 		[JsonProperty("found")]
 		public bool Found { get; internal set; }
+
+		[Obsolete(@"WARNING: IsValid behavior has changed to align with 1.x and 5.x onwards.
+		It now returns true for 404 responses (document not found), where previously it returned
+		false.  Please use .Found to check whether the document was actually found.")]
+		public override bool IsValid => base.IsValid;
 	}
 }

src/Nest/Document/Single/Get/GetResponse.cs

@@ -1,8 +1,5 @@
 using System;
-using System.Collections.Generic;
-using System.Linq.Expressions;
 using Newtonsoft.Json;
-using System.Linq;
 
 namespace Nest
 {
@@ -56,5 +53,10 @@ public class GetResponse<T> : ResponseBase, IGetResponse<T> where T : class
 		public string Routing { get; private set; }
 		public long? Timestamp { get; private set; }
 		public long? Ttl { get; private set; }
+
+		[Obsolete(@"WARNING: IsValid behavior has changed to align with 1.x and 5.x onwards.
+		It now returns true for 404 responses (document not found), where previously it returned
+		false.  Please use .Found to check whether the document was actually found.")]
+		public override bool IsValid => base.IsValid;
 	}
 }