code: private static ByteBuf nextReadableBuf(EmbeddedChannel compressor) {
          for (;;) {
              final ByteBuf buf = compressor.readOutbound();
              if (buf == null) {
                  return null;
              }
              if (!buf.isReadable()) {
                  buf.release();
                  continue;
              }
              return buf;
          }
      }
docs: Read the next compressed {@link ByteBuf} from the {@link EmbeddedChannel} or {@code null} if one does not exist.
  
  @param compressor The channel to read from
  @return The next decoded {@link ByteBuf} from the {@link EmbeddedChannel} or {@code null} if one does not exist