Implement watching a path

Each inotify instance produces events for paths in its watch list. Each
item in the watch list is identified by its watch descriptor. Different
paths can be watched for different events.

Tests/InotifyIntegrationTests/Utilities.swift

@@ -0,0 +1,10 @@
+import Foundation
+
+func withTempDir(_ body: (String) async throws -> Void) async throws {
+	let dir = FileManager.default.temporaryDirectory
+		.appendingPathComponent("InotifyIntegrationTests-\(UUID().uuidString)")
+		.path
+	try FileManager.default.createDirectory(atPath: dir, withIntermediateDirectories: true)
+	defer { try? FileManager.default.removeItem(atPath: dir) }
+	try await body(dir)
+}