code: public InterceptedStream<T> close(String index) {
  
          // Remove associated stream
          InterceptedStream<T> stream = streams.remove(index);
          if (stream == null)
              return null;
  
          // Close stream if it exists
          close(stream.getStream());
          return stream;
  
      }
docs: Closes the stream object associated with the stream having the given
  index, if any, removing it from the map, logging any errors that occur
  during closure, and unblocking any in-progress calls to waitFor() for
  that stream. If no such stream exists within this map, then this
  function has no effect.
  
  @param index
  The index of the stream whose associated stream object should be
  closed.
  
  @return
  The stream associated with the given index, if the stream was stored
  within this map, or null if no such stream exists.