HTS: Design

[steven-sheehy]

Problem
Main nodes are adding a new TokenService to HAPI and Mirror Node needs to add support for it.

Solution
Investigate mirror node impact and construct a design document outlining changes. It's important to come to an agreement on the design and schema of the new service ahead of implementation so we can parallelize the sub-tasks. Document should include:

• Review the proto and provide any feedback to services
• Support new stream file versions (if applicable)
• Support new transaction type and result codes
• Schema for new token related tables
• Token REST APIs
• Token gRPC APIs (if applicable)

Alternatives

Additional Context
Protobuf with both token service and 0.9.0 Transaction changes is available on Maven Central with tag v0.9.0-alpha2.