title: python file-like buffer object
body: <p>I've written a buffer class that provides a File-like interface with <code>read</code>, <code>write</code>, <code>seek</code>, <code>tell</code>, <code>flush</code> methods to a simple string in memory. Of course it is incomplete (e.g. I didn't write <code>readline</code>). It's purpose is to be filled by a background thread from some external data source, but let a user treat it like a file. I'd expect it to contain a relatively small amount of data (maybe 50K max)</p>
  
  <p>Is there a better way to do this instead of writing it from scratch?</p>