private static Http2Exception filterHttp2Exception(Throwable cause, @Nullable Http2Exception http2Ex) {
        if (http2Ex != null) {
            return http2Ex;
        }

        // Do not let Netty use the exception message as debug data, just in case the exception message
        // exposes sensitive information.
        return new Http2Exception(INTERNAL_ERROR, null, cause);
    }
Returns {@code true} if {@link ChannelHandlerContext#close()} has been called.
core/src/main/java/com/linecorp/armeria/internal/common/AbstractHttp2ConnectionHandler.java