public SELF port(int port) {
        checkArgument(port > 0 && port <= 65535,
                      "port: %s (expected: 1-65535)", port);
        this.port = port;
        return self();
    }
Sets the port where a health check request will be sent instead of the original port number
specified by {@link EndpointGroup}'s {@link Endpoint}s. This property is useful when your
server listens to health check requests on a different port.
core/src/main/java/com/linecorp/armeria/client/endpoint/healthcheck/AbstractHealthCheckedEndpointGroupBuilder.java