title: Protobuf ignoring bool and ints values due to default
body: <p>I am converting a json file to string and then the string is converted to proto3 file. </p>
  
  <p>Here is the json file:</p>
  
  <pre><code>{    "a": false,
       "b": 0
  }
  </code></pre>
  
  <p>Here is how I convert my json file to string:</p>
  
  <pre><code>String json =Files.lines(Paths.get(filePath)).collect(Collectors.joining());
  </code></pre>
  
  <p>Here is how I convert my string to proto3 file:</p>
  
  <pre><code>    JsonFormat.parser().ignoringUnknownFields().merge(json,messageBuilder);
     MyProto proto = messageBuilder.build();
  </code></pre>
  
  <p>I have boolean and int fields in my json , the values of some of them are required to be default values (false for boolean and 0 for int).</p>
  
  <p>When I deserialise the above file to proto3 java file then both the above fields are ignored , and my json becomes empty even though I have explicitly set the values(as you can see it in the above json file).</p>
  
  <p>I know that proto3 ignores the default values while deserializing/serializing , however is there any way not to ignore fields which are explicitly set even though they are the default values?</p>