Add a new TODO item.

diff --git a/doc/TODO b/doc/TODO
new file mode 100644 (file)
index 0000000..3c6bbe1
--- /dev/null
+++ b/doc/TODO
@@ -0,0 +1,3 @@
+1. The use of parallel-io limits us to a number of threads equal to
+   the number of capabilities. This doesn't make much sense since the
+   DNS lookups aren't CPU-bound.