How can the var_dump function be used to troubleshoot and understand the structure of the $header variable in PHP when working with email headers?

When working with email headers in PHP, the $header variable may contain complex data structures that are difficult to understand. To troubleshoot and understand the structure of the $header variable, you can use the var_dump function. This function will display the type and value of the variable, allowing you to see its structure and contents more clearly.

// Assuming $header is the variable containing email headers
var_dump($header);