Luke request handler does not know about dynamic fields on other shards fast enough

Add a document with a new (never seen before) dynamic field. It will not be visible through Luke requests on the other shards for quite a while, and there is no documentation regarding exactly how long it will take. The result is that a query to Luke must be made to every shard in the cluster if all dynamic fields are needed.

All shards should be aware of a new dynamic field within seconds, if not milliseconds.