Bench: edits timed at the drawn tile; per-cycle document counts; posted chords

tests/scripts/chord.swift

@@ -0,0 +1,14 @@
+// Posts Command plus a key to one process, flag included.
+import CoreGraphics
+import Foundation
+
+// chord <pid> <virtual key code>
+let pid = pid_t(CommandLine.arguments[1])!
+let code = CGKeyCode(CommandLine.arguments[2])!
+let source = CGEventSource(stateID: .privateState)
+for down in [true, false] {
+    let event = CGEvent(keyboardEventSource: source, virtualKey: code, keyDown: down)!
+    event.flags = .maskCommand
+    event.postToPid(pid)
+    usleep(30_000)
+}