"""Validates the format of a given URL.

This function checks if the provided URL string is valid based on specific criteria:
- The URL must be a non-empty string.
- The URL must use either 'http' or 'https' as its scheme.
- The URL must have a valid network location (netloc).
- The URL length must be less than 2048 characters.

Args:
    url (str): The URL string to be validated.

Returns:
    bool: True if the URL is valid, False otherwise.
"""