OK, it’s not exactly “withering,” but there’s this: The Bush administration’s competitive sourcing program again took a toll on Internal Revenue Service employees, with 218 slated to lose jobs as a result of a public-private contest for information technology work. And that’s not all: The announcement of the technology worker layoffs comes on the heels of Wednesday’s notice that the tax agency plans to close distribution centers in Virginia and California and lay off employees at a third warehouse in Illinois. Employees at the centers maintain stocks of IRS publications and fill orders, but agency officials say their workload is declining at a rate of 6 percent a year as more services move online.