Issue a command and wait for the reply.
Should only be used with commands that return replies on the command channel - do not use for LIST, NLST, MLSD etc.
@param command The command to invoke
@param params The parameters string, may be {@code null}
@return True if successfully completed, false if not, in which casecall {@link #getReplyCode()} or {@link #getReplyString()}to get the reason.
@exception IOException If an I/O error occurs while either sending acommand to the server or receiving a reply from the server.
@since 3.0