The memtier_benchmark tool provides a --data-import option that allows reading
data and optionally key names from file.

The expected file is a comma delimited file (CSV), with the following
columns:

'dumpflags'     an integer bit-mask flags value which should generally be '0'.
'time'          the time the item was inserted or modified, expressed in 
                seconds since the memcached startup.
'exptime'       item's expiration time, expressed in seconds since the 
                memcached startup.                
'nbytes'        length of item data, in bytes.
'nsuffix'       length of flags+length string associated with the item, in bytes.
'it_flags'      a flags bitmask value.
'clsid'         item's slab class ID.
'nkey'          length of key, in bytes.
'key'           the key itself.
'data'          the data itself.

The 'key' and 'data' columns are enclosed in double quotes.  If data in these
columns contains a double quote, it is quoted (i.e., a single " is encoded as
"").

The data column may contain binary data, including non-ASCII characters, NULLs,
CRs and LFs.

