Add HIP-646: Fungible Token Metadata Field

[SimiHunjan]

Problem

HIP-646 introduces new Hedera protobuf changes where the a token metadata field is added to the TokenCreateTransaction and TokenUpdateTransaction. This metadata field will also be returned in the TokenInfoQuery.

HIP

• https://hips.hedera.com/hip/hip-646

Hedera Protobuf

• (link Hedera protobuf PR when available)

Hedera Services Release

Summary of API changes

• Add metadata field to TokenCreateTransaction
• Add metadata field to TokenUpdateTransaction
• Return the metadata of a token from the TokenInfoQuery

Solution

• Design the feature
  • Add to the SDK references repository
• Implement design
• Add example

Alternatives

No response

[SimiHunjan]

Update: This feature will be added in the 0.42 October mainnet release. Could be pushed to the next release if modularization work is not complete.

[SimiHunjan]

Update: This is being pushed to 0.43 Services release.