Type Alias ScanBeginFuture 

pub type ScanBeginFuture<'a> = Pin<Box<dyn Future<Output = Result<(), String>> + Send + 'a>>;

The boxed future an ScannedExcerptSource::begin returns.

Separate from ScanFuture rather than reusing it with an ignored Vec: begin produces nothing, and a signature that says otherwise invites a producer to return rows from it that the scan would drop.

Aliased Type

pub struct ScanBeginFuture<'a> { /* private fields */ }