feat(client): add an accessor for the request body

Allow users to access the body of the request.
Useful when one wants to modify the request based
on the data in the body, e.g. to add checksum headers.

src/client/request.rs

@@ -33,7 +33,7 @@ impl<B> Request<B> {
     /// Read the Request Uri.
     #[inline]
     pub fn uri(&self) -> &Uri { &self.uri }
-
+    
     /// Read the Request Version.
     #[inline]
     pub fn version(&self) -> HttpVersion { self.version }
@@ -46,6 +46,10 @@ impl<B> Request<B> {
     #[inline]
     pub fn method(&self) -> &Method { &self.method }
 
+    /// Read the Request body.
+    #[inline]
+    pub fn body(&self) -> Option<&B> { self.body.as_ref() }
+    
     /// Set the Method of this request.
     #[inline]
     pub fn set_method(&mut self, method: Method) { self.method = method; }