Function create_user 

pub async fn create_user(
    virtual_file_system: &VirtualFileSystem,
    user_name: &str,
    password: &str,
    primary_group: GroupIdentifier,
    user_identifier: Option<UserIdentifier>,
) -> Result<UserIdentifier>

Creates a new user account with the specified parameters.

This function creates a new user in the system by:

1. Generating a new user identifier (if not provided)
2. Adding the user to the Users manager
3. Generating a random salt and hashing the password
4. Creating the user file with all user data

Arguments

• Virtual_file_system - Reference to the virtual file system
• User_name - Username for the new account
• Password - Plain text password for the new account
• Primary_group - Primary group identifier for the user
• User_identifier - Optional specific user identifier (auto-generated if None)

Returns

Returns Ok(UserIdentifier) with the new user’s identifier, or an appropriate error if creation fails.

Errors

This function can fail for various reasons including:

• User identifier generation or assignment failures
• File system operations (directory creation, file writing)
• Users manager operations (adding user)
• Random salt generation failures