add clearer AddJsonBody & AddXmlBody methods

It can be unintuitive that you need to first specify the RequestFormat
is JSON to have the RestRequest serialize data to JSON. This leads to
hard to debug HTTP responses saying that the JSON format is incorrect,
because by default the data is serialized to XML. This is further
compounded by endless suggestions on popular forums and message boards
that you manually need to set the ‘Content-Type’ header to be
‘application/json’ making this a difficult product to use out of the
box.

Author: davidgrupp

RestSharp/IRestRequest.cs

@@ -160,7 +160,8 @@ public interface IRestRequest
 #endif
 
 		/// <summary>
-		/// Serializes obj to format specified by RequestFormat, but passes xmlNamespace if using the default XmlSerializer
+		/// Serializes obj to format specified by RequestFormat, but passes xmlNamespace if using the default XmlSerializer.
+		/// The default format is XML. Change RequestFormat if you wish to use a different serialization format.
 		/// </summary>
 		/// <param name="obj">The object to serialize</param>
 		/// <param name="xmlNamespace">The XML namespace to use when serializing</param>
@@ -169,11 +170,36 @@ public interface IRestRequest
 
 		/// <summary>
 		/// Serializes obj to data format specified by RequestFormat and adds it to the request body.
+		/// The default format is XML. Change RequestFormat if you wish to use a different serialization format.
 		/// </summary>
 		/// <param name="obj">The object to serialize</param>
 		/// <returns>This request</returns>
 		IRestRequest AddBody (object obj);
 
+		/// <summary>
+		/// Serializes obj to JSON format and adds it to the request body.
+		/// </summary>
+		/// <param name="obj">The object to serialize</param>
+		/// <returns>This request</returns>
+		IRestRequest AddJsonBody(object obj);
+
+		/// <summary>
+		/// Serializes obj to XML format and adds it to the request body.
+		/// </summary>
+		/// <param name="obj">The object to serialize</param>
+		/// <returns>This request</returns>
+		IRestRequest AddXmlBody(object obj);
+
+		/// <summary>
+		/// Serializes obj to format specified by RequestFormat, but passes xmlNamespace if using the default XmlSerializer
+		/// Serializes obj to XML format and passes xmlNamespace then adds it to the request body.
+		/// </summary>
+		/// <param name="obj">The object to serialize</param>
+		/// <param name="xmlNamespace">The XML namespace to use when serializing</param>
+		/// <returns>This request</returns>
+		IRestRequest AddXmlBody(object obj, string xmlNamespace);
+		
+
 		/// <summary>
 		/// Calls AddParameter() for all public, readable properties specified in the white list
 		/// </summary>

RestSharp/RestRequest.cs

@@ -206,7 +206,8 @@ private IRestRequest AddFile (FileParameter file)
 		}
 
 		/// <summary>
-		/// Serializes obj to format specified by RequestFormat, but passes xmlNamespace if using the default XmlSerializer
+		/// Serializes obj to format specified by RequestFormat, but passes xmlNamespace if using the default XmlSerializer.
+		/// The default format is XML. Change RequestFormat if you wish to use a different serialization format.
 		/// </summary>
 		/// <param name="obj">The object to serialize</param>
 		/// <param name="xmlNamespace">The XML namespace to use when serializing</param>
@@ -243,6 +244,7 @@ public IRestRequest AddBody (object obj, string xmlNamespace)
 
 		/// <summary>
 		/// Serializes obj to data format specified by RequestFormat and adds it to the request body.
+		/// The default format is XML. Change RequestFormat if you wish to use a different serialization format.
 		/// </summary>
 		/// <param name="obj">The object to serialize</param>
 		/// <returns>This request</returns>
@@ -251,6 +253,41 @@ public IRestRequest AddBody (object obj)
 			return AddBody(obj, "");
 		}
 
+		/// <summary>
+		/// Serializes obj to JSON format and adds it to the request body.
+		/// </summary>
+		/// <param name="obj">The object to serialize</param>
+		/// <returns>This request</returns>
+		public IRestRequest AddJsonBody(object obj)
+		{
+			RequestFormat = DataFormat.Json;
+			return AddBody(obj, "");
+		}
+
+		/// <summary>
+		/// Serializes obj to XML format and adds it to the request body.
+		/// </summary>
+		/// <param name="obj">The object to serialize</param>
+		/// <returns>This request</returns>
+		public IRestRequest AddXmlBody(object obj)
+		{
+			RequestFormat = DataFormat.Xml;
+			return AddBody(obj, "");
+		}
+
+		/// <summary>
+		/// Serializes obj to format specified by RequestFormat, but passes xmlNamespace if using the default XmlSerializer
+		/// Serializes obj to XML format and passes xmlNamespace then adds it to the request body.
+		/// </summary>
+		/// <param name="obj">The object to serialize</param>
+		/// <param name="xmlNamespace">The XML namespace to use when serializing</param>
+		/// <returns>This request</returns>
+		public IRestRequest AddXmlBody(object obj, string xmlNamespace)
+		{
+			RequestFormat = DataFormat.Xml;
+			return AddBody(obj, xmlNamespace);
+		}
+
 		/// <summary>
 		/// Calls AddParameter() for all public, readable properties specified in the white list
 		/// </summary>