module Compression:sig..end
val output_value : out_channel -> 'a -> unitCompression.output_value chan v writes the representation
    of v on channel chan.
    If compression is supported, the marshaled data
    representing value v is compressed before being written to
    channel chan.
    If compression is not supported, this function behaves like
    Stdlib.output_value.
val input_value : in_channel -> 'aCompression.input_value chan reads from channel chan the
    byte representation of a structured value, as produced by
    Compression.output_value, and reconstructs and
    returns the corresponding value.
    If compression is not supported, this function behaves like
    Stdlib.input_value.
val compression_supported : boolReports whether compression is supported.