What are the different types of callback methods available in PHP?

In PHP, there are several types of callback methods available, including: 1. Named function callbacks: These are regular functions defined using the `function` keyword. 2. Anonymous function callbacks: These are functions defined using the `function() {}` syntax without a name. 3. Static method callbacks: These are callbacks that reference static methods of a class. 4. Object method callbacks: These are callbacks that reference non-static methods of an object. Here is an example of how to use an anonymous function callback in PHP:

// Anonymous function callback
$callback = function($param) {
    return "Callback function called with param: $param";
};

// Using the callback
echo $callback("Hello");