Field metadata

So far, we haven’t talked too much about field tags. In this section, we’ll dive into how they are encoded and why they are encoded as such.

First, let’s get a small refresher on what field tags are. They are identifiers for fields that will help Protobuf know into which field to deserialize some data. So, let’s say we have the following field:

uint64 id = 1;

Protobuf decodes some specific data with an ID of 1 (tag), so it will know that this data is meant to be deserialized into the id field. All of this is an abstract explanation of what’s happening, so let’s understand concretely how the field for deserialization is selected.

First, we need to understand that Protobuf only serializes a combination of type, tag, and value. The name of a field is not serialized. We already know how integer values get serialized; later, we will see how it works for other types (string, repeated, and so on). For now, we can focus on...