A gzip file is a sequence of compressed members. Each member has the
following structure:
-2 bytes magic header 0x1f, 0x8b (\037 \213)
+2 bytes magic header 0x1f, 0x8b (\037 \213)
1 byte compression method (0..7 reserved, 8 = deflate)
1 byte flags
bit 0 set: file probably ascii text