Update README.md

README.md

@@ -34,6 +34,7 @@ Example:
 
 ```crystal
 require "protobuf"
+require "tempfile"
 
 enum Foo
   FOO
@@ -56,15 +57,23 @@ struct MyMessage
   # write your methods like you normally would here, if you like.
 end
 
-proto_io = File.read("path/to/encoded/protobuf") # get your IO in some way
+# MyMessage is just a normal struct - let's create one
+msg = MyMessage.new prop_name: 42, prop2: Foo::FOO, optional_prop_name: "Bar"
+puts "Before serialization: #{msg}"
 
-msg = MyMessage.from_protobuf(proto_io) # returns a an instance of MyMessage
-                                  # from a valid protobuf encoded message
+io_memory = msg.to_protobuf # io_memory is an IO::Memory of the encoded message
 
-msg.to_protobuf # return a IO::Memory filled with the encoded message
+# Or write the encoded message into any IO object - such as network, or a file
+tmpfile = Tempfile.open("my_message") do |output_file| 
+    msg.to_protobuf output_file # In this case we use a temporary file
+end
+
+# Now let's decode the message...
+input_file = File.open(tmpfile.path) # open an IO object (the file we just wrote)
+decoded_msg = MyMessage.from_protobuf(input_file) # return an instance of MyMessage
 
-some_io = IO::Memory.new
-msg.to_protobuf(some_io) # fills up the provided IO with the encoded message
+puts "After serialization: #{decoded_msg}"
+tmpfile.delete # clean up the temporary file
 ```
 
 #### Field types