function clbk( error, result ) {
		if ( flg ) {
			// Prevent further processing of collection elements:
			return;
		}
		if ( error ) {
			flg = true;
			debug( 'Encountered an error: %s', error.message );
			return done( error );
		}
		count += 1;
		debug( 'Processed %d of %d collection elements.', count, len );

		debug( 'Test result: %s', !!result );
		if ( result && !flg ) {
			flg = true;
			debug( 'Finished processing a collection.' );
			return done( null, true );
		}
		if ( idx < maxIndex ) {
			return next();
		}
		if ( count === len ) {
			debug( 'Finished processing a collection.' );
			return done( null, false );
		}
	}
Callback invoked once a provided function finishes processing a collection element.

@private
@param {*} [error] - error
@param {*} [result] - test result
@returns {void}