Given a cluster-id and a record-position returns a RID in string format.

Decode the data stream `in` according to `spec`.

Create a function named `command-name` that accepts the argument specified
in `args`. `request-handler` and `response-handler` must be functions. e.g.:

(defcommand test
  [arg-1 arg-2]
  request-handler-fn
  response-handler-fn)

Create a function named `command-name` that accepts the argument specified
in `args`. `request-handler` and `response-handler` must be functions.
`service` is a keyword which indicates the service to which the connection
applies. e.g.:

(defconnection test
  [arg-1 arg-2]
  request-handler-fn
  response-handler-fn
  :db)

Encode `message` applying for each of its fields the function specified in
`spec.`

Parse a RID in string format and returns a vector with cluster-id and
record-position.

Returns a lazy sequence of successive items from coll up to and including
the first item for which `(pred item)` returns true.

Validate `message` against `spec`.