Avoid copies in Facade

KeyCompare.h

@@ -5,6 +5,9 @@
 #include <algorithm>
 #include <string.h>
 
+#include <string>
+using String = std::basic_string<uint8_t>;
+
 inline auto operator<=>(const weaselab::VersionedMap::Key &lhs,
                         const weaselab::VersionedMap::Key &rhs) {
   int cl = std::min(lhs.len, rhs.len);
@@ -16,3 +19,25 @@ inline auto operator<=>(const weaselab::VersionedMap::Key &lhs,
   }
   return lhs.len <=> rhs.len;
 }
+
+inline auto operator<=>(const String &lhs,
+                        const weaselab::VersionedMap::Key &rhs) {
+  int cl = std::min<int>(lhs.size(), rhs.len);
+  if (cl > 0) {
+    int c = memcmp(lhs.data(), rhs.p, cl);
+    if (c != 0) {
+      return c <=> 0;
+    }
+  }
+  return int(lhs.size()) <=> rhs.len;
+}
+
+inline auto operator==(const weaselab::VersionedMap::Key &lhs,
+                       const weaselab::VersionedMap::Key &rhs) {
+  return (lhs <=> rhs) == 0;
+}
+
+inline auto operator!=(const weaselab::VersionedMap::Key &lhs,
+                       const weaselab::VersionedMap::Key &rhs) {
+  return (lhs <=> rhs) != 0;
+}