We have a large subsystem around command dispatch. It lives in these src directories:

• mongo/db/
• mongo/db/commands/
• mongo/s/
• mongo/s/commands/

Notable classes include:

• TypedCommand
• BasicCommand
• ServiceEntryPoint
• Strategy

Since this spans several directories, we should make a new markdown in the docs folder. This is intended to be abstract documentation, describe relationships and state transitions not code in common language.