Function safe_app::ffi::crypto::enc_secret_key_get

#[no_mangle]
pub unsafe extern "C" fn enc_secret_key_get(
    app: *const App, 
    handle: EncryptSecKeyHandle, 
    user_data: *mut c_void, 
    o_cb: extern "C" fn(user_data: *mut c_void, result: *const FfiResult, sec_enc_key: *const AsymSecretKey)
)

Retrieve the private encryption key as raw array.

Callback parameters: user data, error code