heavy-widget.php

<?php

class Heavy_Widget extends WP_Widget {

	public $input_count = 500;

	function __construct() {
		parent::__construct( 'heavy', 'Heavy' );
	}

	function form( $instance ) {
		?>
		<div class="heavy-widget">
			<p>
				<?php $id = 'title'; ?>
				<label for="<?php echo $this->get_field_id( $id ) ?>"><?php echo $id; ?></label>
				<input
					type="text"
					id="<?php echo $this->get_field_id( $id ) ?>"
					name="<?php echo $this->get_field_name( $id ) ?>"
					value="<?php if ( isset( $instance[ $id ] ) ) { echo esc_attr( $instance[ $id ] ); } ?>"
					>
			</p>
			<details>
				<summary>Other fields</summary>
				<?php
				for ( $i = 0; $i < $this->input_count; $i += 1 ) {
					$id = "field$i";
					?>
					<p>
						<label for="<?php echo $this->get_field_id( $id ) ?>"><?php echo $id; ?></label>
						<input
							type="text"
							id="<?php echo $this->get_field_id( $id ) ?>"
							name="<?php echo $this->get_field_name( $id ) ?>"
							value="<?php if ( isset( $instance[ $id ] ) ) { echo esc_attr( $instance[ $id ] ); } ?>"
							>
					</p>
					<?php
				}
			?>
			</details>
		</div>
		<?php
	}

	function widget( $args, $instance ) {
		echo $args['before_widget'];
		echo $this->id;
		print_r( $instance );
		echo $args['after_widget'];
	}

	function update( $new_instance, $old_instance ) {
		$title = isset( $new_instance['title'] ) ? $new_instance['title'] : '';
		$keys = array_slice( array_keys( $new_instance ), 0, 27 );
		$new_instance = array_merge( compact( 'title' ), wp_array_slice_assoc( $new_instance, $keys ) );
		return $new_instance;
	}

}
add_action( 'widgets_init', function() {
	register_widget( 'Heavy_Widget' );
} );

add_action( 'shutdown', function () {
	global $pagenow;
	if ( 'customize.php' !== $pagenow ) {
		return;
	}

	?>
	<!--
	memory_get_peak_usage(): <?php echo number_format_i18n( memory_get_peak_usage() ); ?>
	memory_get_usage(): <?php echo number_format_i18n( memory_get_usage() ); ?>
	-->
	<?php
}, 1000 );