title: Adding a new method to an existing (standard) type
body: <p>I'm writing some code that needs functionality that is almost satisfied by the <code>ReadBytes</code> method in the <code>bufio</code> package. Specifically, that method reads from a <code>Reader</code> until it encounters a particular byte. I need something that reads till it encounters one out of couple of bytes (space, newline and tab mainly).</p>
  
  <p>I looked at the source for the library and I know what to do if I have access to the internal buffer used by <code>bufio</code> structs. Is there any way I could "monkey patch" the package and add another method or two to it? Or another way to get the functionality I need?</p>