builder.setString("foo");
builder.setBytes(ByteString.copyFromUtf8("bar"));
builder.setEnum(A.X);
builder.addIntArray(27);
builder.addSyms(A.Y);
Foo fooInner = builder.build();
Foo fooInArray = builder.build();
builder = Foo.newBuilder(fooInArray);
builder.addFooArray(fooInArray);
builder = Foo.newBuilder(fooInner);
builder.setFoo(fooInner);
Foo foo = builder.build();
System.out.println(foo);
ByteArrayOutputStream bao = new ByteArrayOutputStream();
ProtobufDatumWriter<Foo> w = new ProtobufDatumWriter<Foo>(Foo.class);