THRIFT-5283: add support for Unix Domain Sockets in lib/rs (#2545)

Client: rs
diff --git a/test/tests.json b/test/tests.json
index a8dbef7..3563dc9 100644
--- a/test/tests.json
+++ b/test/tests.json
@@ -679,7 +679,8 @@
       ]
     },
     "sockets": [
-      "ip"
+      "ip",
+      "domain"
     ],
     "transports": [
       "buffered",