Finalize design of new interfaces

[tedsuo]

Step 1

All issues labeled Terminology alignment must be marked as Agreed in order to close this issue.

Terminology: https://github.com/bogdandrutu/openconsensus/issues?q=is%3Aissue+is%3Aopen+label%3A%22Terminology+alignment%22

Step 2

All Agreed upon terminology must be implemented. Close each terminology ticket when this is complete.

Prior Research and Discussion

• https://docs.google.com/document/d/1helXkQkT8ZQm6kSB69465hL8trZ8k53knHOOB_bMK58/edit#
• https://docs.google.com/document/d/1ji0AjLNV1Mhc63GkK42dRAGoqmuPo5TrWuL4aPuTTYQ
• Java: https://docs.google.com/document/d/1gOjNl7nYardzaQJVtJCFJUBUIOwssKN-r9IGyL7HCJc/
• C#:
  https://docs.google.com/document/d/1O98St2QxwdwZuXJ1PhNGDni34K4C0mX6RYgTX6tDL8I
• Golang: https://docs.google.com/document/d/1OjSpMuF_-cLufVEEw2DGVqm2ZVyukhtmfpHeQ8NQU5Q/