protected InterceptedStream<T> getInterceptedStream(String index) {
        return streams.get(index);
    }
Returns the stream having the given index and currently being intercepted
by this filter.

@param index
    The index of the stream to return.

@return
    The stream having the given index, or null if no such stream is
    being intercepted.
guacamole/src/main/java/org/apache/guacamole/tunnel/StreamInterceptingFilter.java