As of Q3 2012, the RadAsyncUpload control supports a ManualUpload property. By setting the ManualUpload property to true users could start the upload of the selected files when they want. In order to start the upload your application code should invoke the startUpload() method from the client side API of the RadAsyncUpload object.
As of Q1 2013, the RadAsyncUpload control supports two more methods, pauseUpload() and resumeUpload() to complete manual upload functionality. Both of them should be invoked from the client side API of the RadAsyncUpload object.
The pauseUpload() method pauses the upload. Note that it pauses right after the currently uploading chunk is uploaded.
The resumeUpload() method resumes the upload that was paused.
When manual upload is used under IE 9/8/7, the upload module is automatically set to IFrame.