Add demo code for prost-types
diff --git a/samplecode/prost-protobuf/enclave/Cargo.toml b/samplecode/prost-protobuf/enclave/Cargo.toml
index bf33608..ac13992 100644
--- a/samplecode/prost-protobuf/enclave/Cargo.toml
+++ b/samplecode/prost-protobuf/enclave/Cargo.toml
@@ -13,6 +13,7 @@
 [dependencies]
 prost = { git = "https://github.com/mesalock-linux/prost-sgx" }
 bytes = { git = "https://github.com/mesalock-linux/bytes-sgx" }
+prost-types = { git = "https://github.com/mesalock-linux/prost-sgx" }
 
 [build-dependencies]
 prost-build = "*"
diff --git a/samplecode/prost-protobuf/enclave/src/lib.rs b/samplecode/prost-protobuf/enclave/src/lib.rs
index ed573a8..41d5c15 100644
--- a/samplecode/prost-protobuf/enclave/src/lib.rs
+++ b/samplecode/prost-protobuf/enclave/src/lib.rs
@@ -41,9 +41,11 @@
 use std::slice;
 
 extern crate prost;
+extern crate prost_types;
 extern crate bytes;
 
 use prost::Message;
+use prost_types::Timestamp;
 
 mod person {
     include!(concat!(env!("OUT_DIR"), "/person.rs"));
@@ -60,5 +62,8 @@
         the_one.email);
     println!("{:?}", the_one);
 
+    let ts = Timestamp { seconds: 0x1234, nanos: 0x5678 };
+    println!("well known types ts = {:?}", ts);
+
     sgx_status_t::SGX_SUCCESS
 }