Several methods from Proc::Async expect that the external program has been spawned (by calling
.start on it), including
close-stdin. If one of those methods is called before
.start was called, they throw an exception of type
Proc::Async.new('echo', :w).say(42);CATCH ;# OUTPUT: «X::Proc::Async::MustBeStarted: Process must be started first before calling 'say'␤»
method method(X::Proc::Async::MustBeStarted --> Str)
Returns the name of the method that was illegally called before starting the external program.