Type Alias StringBuffer 

pub type StringBuffer = String;

UTF-8 encoded string buffer

Guarantees:

• Valid UTF-8 at all times (invariant enforced by type system)
• Contiguous memory layout
• Growable capacity with geometric progression

Memory: ptr + len + capacity (24 bytes on 64-bit) Validation: All mutations validate UTF-8 boundaries

Aliased Type

pub struct StringBuffer { /* private fields */ }