+===================+
                         x-->  Piping functions   +-->   src.pipe(dest)  |
                         x     are set up during     |===================|
                         x     the .pipe method.     |  Event callbacks  |
  +===============+      x                           |-------------------|
  |   Your Data   |      x     They exist outside    | .on('close', cb)  |
  +=======+=======+      x     the data flow, but    | .on('data', cb)   |
          |              x     importantly attach    | .on('drain', cb)  |
          |              x     events, and their     | .on('unpipe', cb) |
+---------v---------+    x     respective callbacks. | .on('error', cb)  |
|  Readable Stream  +----+                           | .on('finish', cb) |
+-^-------^-------^-+    |                           | .on('end', cb)    |
  ^       |       ^      |                           +-------------------+
  |       |       |      |
  |       ^       |      |
  ^       ^       ^      |    +-------------------+         +=================+
  ^       |       ^      +---->  Writable Stream  +--------->  .write(chunk)  |
  |       |       |           +-------------------+         +=======+=========+
  |       |       |                                                 |
  |       ^       |                              +------------------v---------+
  ^       |       +-> if (!chunk)                |    Is this chunk too big?  |
  ^       |       |     emit .end();             |    Is the queue busy?      |
  |       |       +-> else                       +-------+----------------+---+
  |       ^       |     emit .write();                   |                |
  |       ^       ^                                   +--v---+        +---v---+
  |       |       ^-----------------------------------<  No  |        |  Yes  |
  ^       |                                           +------+        +---v---+
  ^       |                                                               |
  |       ^               emit .pause();          +=================+     |
  |       ^---------------^-----------------------+  return false;  <-----+---+
  |                                               +=================+         |
  |                                                                           |
  ^            when queue is empty     +============+                         |
  ^------------^-----------------------<  Buffering |                         |
               |                       |============|                         |
               +> emit .drain();       |  ^Buffer^  |                         |
               +> emit .resume();      +------------+                         |
                                       |  ^Buffer^  |                         |
                                       +------------+   add chunk to queue    |
                                       |            <---^---------------------<
                                       +============+