Standardize unimplemented API failures

crates/libremetaverse-rendering-simple/src/generated.rs

@@ -3,7 +3,7 @@
 #![allow(non_camel_case_types)]
 
 /// `class` shim for C# `LibreMetaverse.Rendering.SimpleRenderer`; members remain intentionally unimplemented.
-#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct SimpleRenderer;
 impl SimpleRenderer {
     pub const CSHARP_NAME: &'static str = "LibreMetaverse.Rendering.SimpleRenderer";

crates/libremetaverse-rendering-simple/src/lib.rs

@@ -5,3 +5,4 @@ mod generated;
 pub use generated::*;
 pub use libremetaverse as core;
 pub use libremetaverse_types as types;
+pub use libremetaverse_types::NotImplemented as Error;