fix: add new Twiml type to deal with constructor overloading issue (#502

)

src/Twilio/Converters/TwimlConverter.cs

@@ -0,0 +1,52 @@
+using System;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace Twilio.Converters
+{
+    /// <summary>
+    /// Convert between strings and a Twiml
+    /// </summary>
+    public class TwimlConverter : JsonConverter
+    {
+        /// <summary>
+        /// Write value to JsonWriter
+        /// </summary>
+        /// <param name="writer">Writer to write to</param>
+        /// <param name="value">Value to write</param>
+        /// <param name="serializer">unused</param>
+        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        {
+            var t = JToken.FromObject(value.ToString());
+            t.WriteTo(writer);
+        }
+
+        /// <summary>
+        /// Convert a string to a Twiml
+        /// </summary>
+        /// <param name="reader">JsonReader to read from</param>
+        /// <param name="objectType">unused</param>
+        /// <param name="existingValue">unused</param>
+        /// <param name="serializer">unused</param>
+        /// <returns>Converted Twiml</returns>
+        public override object ReadJson(
+            JsonReader reader,
+            Type objectType,
+            object existingValue,
+            JsonSerializer serializer
+        )
+        {
+            return new Types.Twiml(reader.Value as string);
+        }
+
+        /// <summary>
+        /// Determines if an object converted to a Twiml
+        /// </summary>
+        /// <param name="objectType">Type of object</param>
+        /// <returns>true if an object can be converted; false otherwise</returns>
+        public override bool CanConvert(Type objectType)
+        {
+            return objectType == typeof(Enum);
+        }
+    }
+}

src/Twilio/Types/Twiml.cs

@@ -0,0 +1,39 @@
+namespace Twilio.Types
+{
+    /// <summary>
+    /// Twiml endpoint
+    /// </summary>
+    public class Twiml
+    {
+        private readonly string _twiml;
+
+        /// <summary>
+        /// Create a new Twiml
+        /// </summary>
+        /// <param name="twiml">Twiml</param>
+        public Twiml(string twiml)
+        {
+            _twiml = twiml;
+        }
+
+        /// <summary>
+        /// Add implicit constructor for Twiml to make it assignable from string
+        /// </summary>
+        /// <param name="twiml">Twiml</param>
+        /// <returns></returns>
+        public static implicit operator Twiml(string twiml)
+        {
+            return new Twiml(twiml);
+        }
+
+        /// <summary>
+        /// Convert to string
+        /// </summary>
+        /// <returns>String representation</returns>
+        public override string ToString()
+        {
+            return _twiml;
+        }
+    }
+}
+