How can PHP developers optimize their code for performance and efficiency when transitioning to PHP 7, considering new features and improvements?

To optimize PHP code for performance and efficiency when transitioning to PHP 7, developers can take advantage of new features such as scalar type declarations, return type declarations, and the null coalescing operator. By using these features effectively, developers can write more concise and readable code that runs faster and consumes fewer resources.

// Example of using scalar type declarations and return type declarations
function addNumbers(int $a, int $b): int {
    return $a + $b;
}

// Example of using the null coalescing operator
$variable = $someValue ?? 'default';