Type Alias AsyncCallback 

pub type AsyncCallback = unsafe extern "C" fn(result: *const c_void, error: *const c_char, ctx: *mut c_void);

Available on crate feature async only.

Callback signature used by all avp_*_async Swift thunks.

• result – opaque result pointer (JSON *mut c_char or packed bool); null when an error occurred.
• error – null-terminated error message; null on success.
• ctx – opaque context returned unchanged to the Rust completion handler.