document .w, .started

lib/Type/Proc/Async.pod

@@ -104,6 +104,14 @@ Note that you cannot call C<stderr> both with and without C<:bin> on the same
 object; it will throw an exception of type L<X::Proc::Async::CharsOrBytes> if
 you try.
 
+=head2 method w
+
+    method w(Proc::Async:D:)
+
+Returns a true value if C<:w> as passed to the constructor, that is, if the
+external program is started with its input stream made available to input from
+the program through C<print>, C<say> and C<write>.
+
 =head2 method start
 
     method start(Proc::Async:D:, :$scheduler = $*SCHEDULER) returns Promise:D
@@ -117,6 +125,12 @@ called before, an exception of L<type
 X::Proc::Async::AlreadyStarted|/type/X::Proc::Async::AlreadyStarted> is
 thrown.
 
+=head2 method started
+
+    method started(Proc::Async:D:) returns Bool:D
+
+Returns C<False> before C<.start> has been called, and C<True> afterwards.
+
 =head2 method path
 
     method path(Proc::Async:D:)