And Rachel Maddow gave a master class in just that on her MSNBC show Tuesday night.

With huge numbers of viewers tuned in because of her earlier tweet that she had obtained President Trump’s tax returns, she talked . . . and talked . . . and talked. For an eternity — or close to 20 minutes, which certainly felt like an eternity — viewers heard about everything except the actual news. We got Russian oligarchs, Cypriot banks, the firing of former national security adviser Michael Flynn and much more.

“Haven’t seen this much windup since El Duque,” quipped Maggie Haberman, a New York Times reporter, referringon Twitter to former Yankee Orlando Hernandez’s pitching style.

About 10 minutes in, I started wondering what would have happened if Maddow, rather than David Fahrenthold of The Washington Post, had been sent the “Access Hollywood” video? How long, how long, would we have waited to find out what a really famous guy can grab ’em by?

Maddow’s reveal, when it finally came, was interesting if underwhelming: Trump paid $38 million in federal taxes in 2005 at about a 25 percent rate and took a huge write-down. (Donald Trump Jr. tweeted his sarcastic thanks to Maddow for showing his father’s business success; and indeed, these figures were not damaging to Trump in the way that a New York Times report last fall on his leaked 1995 taxes were.)

In the nearly 90 minutes between Maddow’s initial tweet and the actual news being pronounced on her show by her star guest, investigative reporter David Cay Johnston, the White House itself had gone on the offensive to release the numbers, and the Daily Beast, where Johnston writes a column, had published a story on the same.

And by then, talk on Twitter had already turned to whether Trump himself had released the returns, possibly as a shiny-object distraction from the Republican health-care bill.

The smart money says no: Much more likely, they emanated from the unsuccessful and ill-advised 2006 lawsuit that Trump filed against former New York Times reporter and Trump biographer Timothy O’Brien in which the same returns — 2005 — were provided in discovery.

Maddow’s slow reveal had its defenders, such as viewer Karen Charmatz, who tweeted: “I like the way she explains things. Sometimes it’s proper to contextualize an issue. This is one of those times.”

But mostly, it had its critics, including Jason Del Rey of Recode: “Maddow just convinced millions more to cut the cable cord.”

And, happily, the show provided educational material beyond how to bury the lede. Dictionary.com said its top request for word definition was for “transom,” after Johnston described how he received the documents “over the transom,” meaning that they arrived unrequested and in this case, in the old-fashioned U.S. mail — the second time Trump tax returns have come to a reporter that way in recent months.

And the cable-cutting generation younger than 35 who scrambled to stream the Maddow show or watch from a bar or a parent’s home seemed to learn something, too: That the world of cable TV has its own language and its own inexplicable mores.

Maddow’s approach was in keeping with how she conducts her highly rated show every night. This is not a woman who believes in cutting to the chase.

As she told Michael Grynbaum of the Times in a recent interview, Maddow never assumes that her viewers have all the information and context they need: “There’s new people here every night. I definitely feel like, hey, if you’re new, let me meet you where you are.”

In the end, a scoop is a scoop, and Maddow certainly milked it for all it was worth. To her credit, she also put the crucial subject of Trump’s finances squarely back in the national conversation.

The president’s Tuesday night complaint that Maddow must be “desperate for ratings” — and that the publication of the return was illegal — doesn’t hold up.The publication of newsworthy material is not against the law; the president’s tax returns, long denied to the public, certainly meet that test.

In addition to Maddow’s not-so-short course in burying the lede, and the new understanding of how “over the transom” works, we all learned something else: Just how fast President Trump can move to release his tax returns when he wants to.