broadcastQueries and subscribeToQuery - where are docs?

[wzup]

Intended outcome:
Docs for subscribeToQuery and broadcastQueries.

Actual outcome:
Search on project's site returns nothing for these methods.
But whole community uses them. Just search this repo issues. You'll get 5 open and 19 closed issued for broadcastQueries alone.

How to reproduce the issue:
Just search this repo issues. You'll get 5 open and 19 closed issued for broadcastQueries alone.

Versions

  System:
    OS: macOS High Sierra 10.13.4
  Binaries:
    Node: 8.11.3 - /usr/local/bin/node
    npm: 5.6.0 - /usr/local/bin/npm
  Browsers:
    Chrome: 68.0.3440.106
    Safari: 11.1
  npmPackages:
    apollo-boost: ^0.1.4 => 0.1.10 
    apollo-cache-inmemory: ^1.1.0 => 1.2.5 
    apollo-client: ^2.0.3 => 2.3.5 
    apollo-link: ^1.0.3 => 1.2.2 
    apollo-link-http: ^1.2.0 => 1.5.4 
    react-apollo: ^2.1.1 => 2.1.9 

[wzup]

Same #3943

[hwillson]

subscribeToQuery is no longer used, and broadcastQueries is part of the internal (non-public) API. We don't tend to document internal API functionality, since using it is outside the scope of normal Apollo Client use. If you're interested in seeing what it does, take a look at the QueryManager source.