index.js
function CountStream (opts) {
  if (!(this instanceof CountStream)) return new CountStream(opts)

  stream.PassThrough.call(this, opts)
  this.destroyed = false
  this.size = 0
}
function CountStream (opts) {
  if (!(this instanceof CountStream)) return new CountStream(opts)

  stream.PassThrough.call(this, opts)
  this.destroyed = false
  this.size = 0
}
function CountStream ( opts ) { if ( ! ( this instanceof CountStream ) ) return new CountStream ( opts ) stream . PassThrough . call ( this , opts ) this . destroyed = false this . size = 0 }
create a new count stream obj? -> tstream
create a new count stream obj? - > tstream