function createClbk( i ) {
		var file = files[ i ];
		var k = i + 1;

		return onExists;
		/**
		* Callback to be invoked upon determining if a file path exists.
		*
		* @private
		* @param {(Error|null)} error - error object
		* @param {boolean} bool - boolean indicating if a file path exists
		* @returns {void}
		*/
		function onExists( error, bool ) {
			if ( error ) {
				debug( 'Encountered an error while resolving file: %s (%d of %d). Error: %s', file, k, len, error.message );
				return clbk( error );
			}
			if ( !bool ) {
				debug( 'Unable to resolve file: %s (%d of %d). File does not exist.', file, k, len );
				error = new Error( format( 'unexpected error. File does not exist. Unable to resolve file: %s.', file ) );
				return clbk( error );
			}
			debug( 'Resolved file: %s (%d of %d). File: %s.', file, k, len, file );
			out[ i ] = file;

			count += 1;
			debug( 'Resolved %d of %d files.', count, len );
			if ( count === len ) {
				debug( 'Resolved all files.' );
				return clbk( null, out, idx );
			}
		}
	}
Returns a callback to be invoked upon determining if a file path exists.

@private
@param {NonNegativeInteger} i - index
@returns {Callback} callback