chore: checkpoint before Python removal

vendor/pin-project-internal/src/pin_project/mod.rs

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+mod args;
+mod attribute;
+mod derive;
+
+use proc_macro2::TokenStream;
+use syn::Error;
+
+/// The annotation for pinned type.
+const PIN: &str = "pin";
+
+pub(crate) fn attribute(args: &TokenStream, input: TokenStream) -> TokenStream {
+    attribute::parse_attribute(args, input).unwrap_or_else(Error::into_compile_error)
+}
+
+pub(crate) fn derive(input: TokenStream) -> TokenStream {
+    derive::parse_derive(input).unwrap_or_else(Error::into_compile_error)
+}