@Override
    protected final void onConnectionError(ChannelHandlerContext ctx, boolean outbound,
                                           Throwable cause, Http2Exception http2Ex) {
        if (handlingConnectionError) {
            return;
        }

        handlingConnectionError = true;
        if (Exceptions.isExpected(cause) || isGoAwaySentException(cause, connection())) {
            logger.trace("{} HTTP/2 connection error:", ctx.channel(), cause);
        } else {
            logger.warn("{} HTTP/2 connection error:", ctx.channel(), cause);
        }
        super.onConnectionError(ctx, outbound, cause, filterHttp2Exception(cause, http2Ex));
    }
Returns {@code true} if {@link ChannelHandlerContext#close()} has been called.
core/src/main/java/com/linecorp/armeria/internal/common/AbstractHttp2ConnectionHandler.java