createBody
public RandomAccessBody createBody()
                            throws IOException
Creates a new instance of the request body to be read. While each invocation of this method is supposed to create
 a fresh instance of the body, the actual contents of all these body instances is the same. For example, the body
 needs to be resend after an authentication challenge of a redirect.
- Specified by:
 
createBody in interface BodyGenerator 
- Returns:
 - The request body, never 
null. 
- Throws:
 
IOException - If the body could not be created.