Feature/system.text.json (#192)

Initial support for System.Text.Json and some refactoring

CryptoExchange.Net/Objects/ParameterCollection.cs

@@ -1,5 +1,6 @@
 using CryptoExchange.Net.Attributes;
 using CryptoExchange.Net.Converters;
+using CryptoExchange.Net.Converters.SystemTextJson;
 using System;
 using System.Collections.Generic;
 using System.Globalization;
@@ -158,6 +159,17 @@ namespace CryptoExchange.Net.Objects
             Add(key, EnumConverter.GetString(value)!);
         }
 
+        /// <summary>
+        /// Add an enum value as the string value as mapped using the <see cref="MapAttribute" />
+        /// </summary>
+        /// <param name="key"></param>
+        /// <param name="value"></param>
+        public void AddEnumAsInt<T>(string key, T value)
+        {
+            var stringVal = EnumConverter.GetString(value);
+            Add(key, EnumConverter.GetString(int.Parse(stringVal))!);
+        }
+
         /// <summary>
         /// Add an enum value as the string value as mapped using the <see cref="MapAttribute" />. Not added if value is null
         /// </summary>
@@ -168,5 +180,19 @@ namespace CryptoExchange.Net.Objects
             if (value != null)
                 Add(key, EnumConverter.GetString(value));
         }
+
+        /// <summary>
+        /// Add an enum value as the string value as mapped using the <see cref="MapAttribute" />. Not added if value is null
+        /// </summary>
+        /// <param name="key"></param>
+        /// <param name="value"></param>
+        public void AddOptionalEnumAsInt<T>(string key, T? value)
+        {
+            if (value != null)
+            {
+                var stringVal = EnumConverter.GetString(value);
+                Add(key, int.Parse(stringVal));
+            }
+        }
     }
 }

CryptoExchange.Net/Objects/TraceLogger.cs

@@ -31,8 +31,8 @@ namespace CryptoExchange.Net.Objects
     /// </summary>
     public class TraceLogger : ILogger
     {
-        private string? _categoryName;
-        private LogLevel _logLevel;
+        private readonly string? _categoryName;
+        private readonly LogLevel _logLevel;
 
         /// <summary>
         /// ctor
@@ -46,7 +46,7 @@ namespace CryptoExchange.Net.Objects
         }
 
         /// <inheritdoc />
-        public IDisposable BeginScope<TState>(TState state) => null!;
+        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null!;
 
         /// <inheritdoc />
         public bool IsEnabled(LogLevel logLevel) => (int)logLevel < (int)_logLevel;