Improve documentation

Sources/MockingURLProtocol.swift

@@ -106,26 +106,23 @@ private extension URLRequest {
         return try? JSONSerialization.jsonObject(with: httpBody, options: .fragmentsAllowed) as? [String: Any]
     }
 
+    /// We need to use the http body stream data as the URLRequest once launched converts the `httpBody` to this stream of data.
     private func httpBodyStreamData() -> Data? {
         guard let bodyStream = self.httpBodyStream else { return nil }
 
         bodyStream.open()
 
         // Will read 16 chars per iteration. Can use bigger buffer if needed
         let bufferSize: Int = 16
-
         let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: bufferSize)
-
         var data = Data()
 
         while bodyStream.hasBytesAvailable {
-
-            let readDat = bodyStream.read(buffer, maxLength: bufferSize)
-            data.append(buffer, count: readDat)
+            let readData = bodyStream.read(buffer, maxLength: bufferSize)
+            data.append(buffer, count: readData)
         }
 
         buffer.deallocate()
-
         bodyStream.close()
 
         return data