ect acts as a sink for octets (either individual octets or
  vectors of octets), and is a source for octets in a compressed data
  format. The compressed octet data is provided to a user-defined
  callback that can write it to a stream, copy it to another vector,
  etc.

<p>Salza2 has built-in compressors that support the ZLIB, DEFLATE, and
  GZIP data formats. The classes and generic function protocol are
  available to make it easy to support similar formats via subclassing
  and new methods. ZLIB and GZI