Add loading multiple files benchmark

Author: soutaro

benchmarks2.rb

@@ -0,0 +1,22 @@
+require "rbs"
+require "benchmark/ips"
+require "csv"
+require "pathname"
+
+files = {}
+ARGV.each do |file|
+  content = File.read(file)
+  files[file] = RBS::Buffer.new(content: content, name: Pathname(file))
+end
+
+puts "Benchmarking parsing #{files.size} files..."
+
+Benchmark.ips do |x|
+  x.report("parsing") do
+    files.each do |file, content|
+      RBS::Parser.parse_signature(content)
+    end
+  end
+
+  x.compare!
+end