index.js
function _bytes (n, fn) {
  assert(!this._parserCallback, 'there is already a "callback" set!');
  assert(isFinite(n) && n > 0, 'can only buffer a finite number of bytes > 0, got "' + n + '"');
  if (!this._parserInit) init(this);
  debug('buffering %o bytes', n);
  this._parserBytesLeft = n;
  this._parserCallback = fn;
  this._parserState = BUFFERING;
}
function _bytes (n, fn) {
  assert(!this._parserCallback, 'there is already a "callback" set!');
  assert(isFinite(n) && n > 0, 'can only buffer a finite number of bytes > 0, got "' + n + '"');
  if (!this._parserInit) init(this);
  debug('buffering %o bytes', n);
  this._parserBytesLeft = n;
  this._parserCallback = fn;
  this._parserState = BUFFERING;
}
function _bytes ( n , fn ) { assert ( ! this . _parserCallback , 'there is already a "callback" set!' ) ; assert ( isFinite ( n ) && n > 0 , 'can only buffer a finite number of bytes > 0, got "' + n + '"' ) ; if ( ! this . _parserInit ) init ( this ) ; debug ( 'buffering %o bytes' , n ) ; this . _parserBytesLeft = n ; this . _parserCallback = fn ; this . _parserState = BUFFERING ; }
Buffers `n` bytes and then invokes `fn` once that amount has been collected.

@param {Number} n the number of bytes to buffer
@param {Function} fn callback function to invoke when `n` bytes are buffered
@api public
Buffers n bytes and then invokes fn once that amount has been collected .