chore: checkpoint before Python removal

vendor/bitflags/examples/custom_derive.rs

@@ -0,0 +1,23 @@
+//! An example of implementing the `BitFlags` trait manually for a flags type.
+
+use std::str;
+
+use bitflags::bitflags;
+
+// Define a flags type outside of the `bitflags` macro as a newtype
+// It can accept custom derives for libraries `bitflags` doesn't support natively
+#[derive(zerocopy::IntoBytes, zerocopy::FromBytes, zerocopy::KnownLayout, zerocopy::Immutable)]
+#[repr(transparent)]
+pub struct ManualFlags(u32);
+
+// Next: use `impl Flags` instead of `struct Flags`
+bitflags! {
+    impl ManualFlags: u32 {
+        const A = 0b00000001;
+        const B = 0b00000010;
+        const C = 0b00000100;
+        const ABC = Self::A.bits() | Self::B.bits() | Self::C.bits();
+    }
+}
+
+fn main() {}