Decompresses messages according to the selected algorithm. Supported decompression types are: gzip, zlib, bzip2, flate.
string The decompression algorithm to use.
array An optional array of message indexes of a batch that the processor should apply to.
If left empty all messages are processed. This field is only applicable when
batching messages at the input level.
Indexes can be negative, and if so the part will be selected from the end counting backwards starting from -1.