code: @Override
      public void onError(ChannelHandlerContext ctx, boolean outbound, Throwable cause) {
          Http2Exception embedded = getEmbeddedHttp2Exception(cause);
          if (isStreamError(embedded)) {
              onStreamError(ctx, outbound, cause, (StreamException) embedded);
          } else if (embedded instanceof CompositeStreamException) {
              CompositeStreamException compositException = (CompositeStreamException) embedded;
              for (StreamException streamException : compositException) {
                  onStreamError(ctx, outbound, cause, streamException);
              }
          } else {
              onConnectionError(ctx, outbound, cause, embedded);
          }
          ctx.flush();
      }
docs: Central handler for all exceptions caught during HTTP/2 processing.