Many API share a common approach of Reader and Writer.
This interface and the AbstractWriter provides the general needs
to open, convert to binary or char stream and dispose them.
author  Johann Sorel

Set the writer output.
The type of output supported may change based on the writer.
param  output target to write into,
throws  IOException if output type is not supported.

Get the currently set output.
return  Object can be null.

Release this writer, freeing any additional resources opened
by the writer.
Implementation may be reusable other not.
throws  IOException if freeing all resources failed.