Import 'regex-syntax' package vesion 0.6.17

* Add OWNERS
Bug: 152884384
Test: make

Change-Id: I760a69ffc851039ceaff58980deece308a426aed
diff --git a/src/either.rs b/src/either.rs
new file mode 100644
index 0000000..7ae41e4
--- /dev/null
+++ b/src/either.rs
@@ -0,0 +1,8 @@
+/// A simple binary sum type.
+///
+/// This is occasionally useful in an ad hoc fashion.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum Either<Left, Right> {
+    Left(Left),
+    Right(Right),
+}