Negotiate a SeedLink connection in uni-station mode and issue the
DATA command. This is compatible with SeedLink Protocol version 2 or
If selectors are defined, then the string is parsed on space and each
selector is sent.
If ‘seqnum’ != -1 and the SLCD ‘resume’ flag is true then data is
requested starting at seqnum.
- SeedLinkException on error.
- IOException if an I/O error occurs.