chore: checkpoint before Python removal

vendor/zerovec/src/varzerovec/error.rs

@@ -0,0 +1,24 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use core::fmt::Display;
+
+#[derive(Debug)]
+pub enum VarZeroVecFormatError {
+    /// The byte buffer was not in the appropriate format for VarZeroVec.
+    Metadata,
+    /// One of the values could not be decoded.
+    Values(crate::ule::UleError),
+}
+
+impl core::error::Error for VarZeroVecFormatError {}
+
+impl Display for VarZeroVecFormatError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self {
+            Self::Metadata => write!(f, "VarZeroVecFormatError: metadata"),
+            Self::Values(e) => write!(f, "VarZeroVecFormatError: {e}"),
+        }
+    }
+}