reactiveValues objectshiny offers no public way to delete a key from a shiny::reactiveValues()
object -- assigning NULL stores a NULL value but leaves the key in
names(). trim_rv() removes the named entries outright and invalidates
the affected reactive dependencies, so a key can be truly dropped (and
later re-added) -- for instance when a variadic block argument is unlinked.
trim_rv(x, rm)x, invisibly.
A reactiveValues object.
Character vector of keys to remove; all must be present in x.