HttpVersion update

Added LibraryHelpers.CreateHttpClientMessageHandle to standardize HttpMessageHandler creation
Added REST client option for selecting HTTP protocol version
Added REST client option for HTTP client keep alive interval
Added HttpVersion to WebCallResult responses
Updated request logic to default to using HTTP version 2.0 for dotnet core

CryptoExchange.Net/Interfaces/IRequest.cs

@@ -28,6 +28,10 @@ namespace CryptoExchange.Net.Interfaces
         /// </summary>
         Uri Uri { get; }
         /// <summary>
+        /// HTTP protocol version
+        /// </summary>
+        Version HttpVersion { get; }
+        /// <summary>
         /// internal request id for tracing
         /// </summary>
         int RequestId { get; }

CryptoExchange.Net/Interfaces/IRequestFactory.cs

@@ -1,4 +1,5 @@
 using CryptoExchange.Net.Objects;
+using CryptoExchange.Net.Objects.Options;
 using System;
 using System.Net.Http;
 
@@ -12,25 +13,21 @@ namespace CryptoExchange.Net.Interfaces
         /// <summary>
         /// Create a request for an uri
         /// </summary>
-        /// <param name="method"></param>
-        /// <param name="uri"></param>
-        /// <param name="requestId"></param>
-        /// <returns></returns>
-        IRequest Create(HttpMethod method, Uri uri, int requestId);
+        IRequest Create(Version httpRequestVersion, HttpMethod method, Uri uri, int requestId);
 
         /// <summary>
         /// Configure the requests created by this factory
         /// </summary>
-        /// <param name="requestTimeout">Request timeout to use</param>
+        /// <param name="options">Rest client options</param>
         /// <param name="httpClient">Optional shared http client instance</param>
-        /// <param name="proxy">Optional proxy to use when no http client is provided</param>
-        void Configure(ApiProxy? proxy, TimeSpan requestTimeout, HttpClient? httpClient = null);
+        void Configure(RestExchangeOptions options, HttpClient? httpClient = null);
 
         /// <summary>
         /// Update settings
         /// </summary>
         /// <param name="proxy">Proxy to use</param>
         /// <param name="requestTimeout">Request timeout to use</param>
-        void UpdateSettings(ApiProxy? proxy, TimeSpan requestTimeout);
+        /// <param name="httpKeepAliveInterval">Http client keep alive interval</param>
+        void UpdateSettings(ApiProxy? proxy, TimeSpan requestTimeout, TimeSpan? httpKeepAliveInterval);
     }
 }

CryptoExchange.Net/Interfaces/IResponse.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Net;
 using System.Threading.Tasks;
@@ -15,6 +16,11 @@ namespace CryptoExchange.Net.Interfaces
         /// </summary>
         HttpStatusCode StatusCode { get; }
 
+        /// <summary>
+        /// Http protocol version
+        /// </summary>
+        Version HttpVersion { get; }
+
         /// <summary>
         /// Whether the status code indicates a success status
         /// </summary>