[feature request] latest known blockHeight

[Hebilicious]

Issue

When running the events or actions query, there is no way to know what is the latest blockHeight currently in the database when the results set is empty.

This information is present within the SQL queries (height = (SELECT max(height) FROM blocks)) but it's not directly exposed by the graphql server (only distanceFromMaxBlockHeight is)

It could be helpful to know what is the maxBlockHeight when the query return an empty set of results.

Proposed solution :

One way would be to return a parent type from the events and actions query.

union Output = EventOutput | ActionOutput
type QueryResult {
	currentBlockInfo: BlockInfo
	output: [Output]!
}
type Query {
  events(input: EventFilterOptionsInput!): [QueryResult]!
  actions(input: ActionFilterOptionsInput!): [QueryResult]!
}

Since that would be a breaking change, it might be easier to add a separated query :

type Query {
  events(input: EventFilterOptionsInput!): [EventOutput]!
  actions(input: ActionFilterOptionsInput!): [ActionOutput]!
  currentBlockInfo: BlockInfo!
}

[45930]

We probably won't get around to this this week, then we are taking a week off. I think this is a good idea though. I will take a look in the new year!