Challenge: Manual Borsh-Style Serialization in Rust

To truly understand how Borsh works under the hood, you'll manually serialize account data to bytes using Rust's standard library.

Your Task

Implement serialize_account(owner, balance, frozen) that converts account fields to a Vec<u8> with this Borsh-like layout:

• 4 bytes: owner name length as u32 (little-endian)
• N bytes: owner name as UTF-8 bytes
• 8 bytes: balance as u64 (little-endian)
• 1 byte: frozen flag (0 = false, 1 = true)

Requirements:

• Use u32::to_le_bytes() for the length prefix
• Use .as_bytes() to get UTF-8 bytes from a &str
• Use u64::to_le_bytes() for the balance
• Push 0u8 or 1u8 for the boolean
• Total size should be 4 + owner.len() + 8 + 1 bytes

Rust APIs:

• Vec::new(), Vec::extend_from_slice()
• u32::to_le_bytes(), u64::to_le_bytes()
• str::as_bytes(), str::len()