code: public boolean isValidStreamId(Number streamId) {
          double d = streamId.doubleValue();
          if (log.isTraceEnabled()) {
              log.trace("Checking validation for streamId {}; reservedStreams: {}; streams: {}, connection: {}", new Object[] { d, reservedStreams, streams, sessionId });
          }
          if (d <= 0 || !reservedStreams.contains(d)) {
              log.warn("Stream id: {} was not reserved in connection {}", d, sessionId);
              // stream id has not been reserved before
              return false;
          }
          if (streams.get(d) != null) {
              // another stream already exists with this id
              log.warn("Another stream already exists with this id in streams {} in connection: {}", streams, sessionId);
              return false;
          }
          if (log.isTraceEnabled()) {
              log.trace("Stream id: {} is valid for connection: {}", d, sessionId);
          }
          return true;
      }
docs: Returns whether or not a given stream id is valid.
  
  @param streamId
  stream id
  @return true if its valid, false if its invalid