August 10, 16:30 (UTC): Carl Mäsak starts a thread about the syntax for embedded comments on p6l. Various different ideas are being discussed for about a day.

August 11, 17:28 (UTC): Larry Wall decides on the new syntax and commits his changes to the specification.

August 11, 17:43 (UTC): (that is, 15 minutes later) Larry Wall updates the official grammar to parse the new syntax.

August 11, 17:51 (UTC): (that is, another 8 minutes later): Moritz Lenz (me) updates the spectests to reflect the new syntax..

August 11, 18:11 (UTC): (that is, another 20 minutes later): Patrick Michaud updates Rakudo to the new syntax.

So from the time of the decision it took less than an hour to be adopted by the test suite and two major implementations.