def read_regexp
      string = read_string(cache: false)
      options = read_byte

      result = Regexp.new(string, options)
      @object_cache << result
      result
    end
def read_regexp
      string = read_string(cache: false)
      options = read_byte

      result = Regexp.new(string, options)
      @object_cache << result
      result
    end
Reads and returns Regexp from an input stream

 @example
   r = /regexp/mix
 is encoded as
   '/', 'regexp', r.options.chr