TYPE:
  //date
  //datetime
  //or
 
  /meta/
  /extra/
  /text/
 
errors that indicate source of first problem
instruction to learn composite schema
Rx for API
parameterized composite types
Rx-assisted emitter
 
Rx Capsule - a data structure that declares the promised schema of contents
  * assert what types / versions are available
  * version can be a type, so you can range it or use any[ranges]
  * { capsule-version, schema-of-payload, payload, type-avail-assertions }