Summary:

• Backed by Map
  • With .set(), .get(), .has() methods
• Backed by pbf
  • With .toBuffer() and .parseBuffer() methods

References:

• https://www.npmjs.com/package/pbf
• https://docs.microsoft.com/en-us/cpp/c-language/cpp-integer-limits

Flow: 1.

tag === 1 is always a string.