def encoder(encoder_spec = nil, *encoder_args, &block)
      return @encoder if encoder_spec.nil?
      @encoder = Rackstash::Encoder.build(encoder_spec, *encoder_args, &block)
    end
def encoder(encoder_spec = nil, *encoder_args, &block)
      return @encoder if encoder_spec.nil?
      @encoder = Rackstash::Encoder.build(encoder_spec, *encoder_args, &block)
    end
Get or set the encoder for the log {#adapter}. If this value is not
 explicitly defined, it defaults to the #{adapter}'s default encoder.

 @param encoder_spec (see Rackstash::Encoder.build)
 @param encoder_args (see Rackstash::Encoder.build)
 @param block (see Rackstash::Encoder.build)
 @raise [TypeError] if the given `encoder` does not respond to the `encode`
   method
 @return [#encode] the newly set encoder (if given) or the currently
   defined one
 @see #encoder=