title: How to know actual size of byte buffer`s content in nodejs?
body: <p>I get files as byte buffers and cannot use fs.stat() method.
  So I am try to use buf.length but this length refers to the amount of memory allocated for the buffer object and not actually the content size. 
  For example I have file with with size 22,449 bytes. 
  buf.length returns for 39804 for it.</p>