+enzstd creates Zstandard compressed stream of frames, where each frame
+holds exactly single WARC record. It also explicitly adds checksum.
+Utility takes records from stdin, where each record has 64-bit
+big-endian length prefix.
+
+unzstd decompressed Zstandard frames stream from stdin to stdout. If
+stream starts with the dictionary (either compressed, or uncompressed)
+it is loaded first. If 3rd file descriptor is opened, then each frame's
+offset (its size) with decompressed data size is printed in
+tab-separated format. If the stream contains dictionary, then first
+frame's data size equals to zero.