text: const { Readable, Writable, pipeline } = require ( 'stream' );
  
  const read_str = new Readable ();
  const write_str = new Writable ();
  
  
  write_str._write = ( chunk, encoding, next ) => {
      console.log ( chunk.toString () );
      next ();
  };
  
  
  debugger;
  pipeline (
      read_str,
      write_str,
      ( err ) => {
          if ( err ) {
              console.error ( 'Pipeline failed.', err );
          }
          else {
              console.log ( 'Pipeline succeeded.' );
          }
      }
  );
  
  read_str.push ( 'chunk_1 \n' );
  read_str.push ( 'chunk_2 \n' );
  
  