Add support for getting hardware concurrency.

lib/async/container.rb

@@ -20,11 +20,19 @@
 
 require_relative 'container/threaded'
 
+require 'etc'
+
 module Async
 	# Manages a reactor within one or more threads.
 	module Container
 		def self.new(**options, &block)
 			Threaded.new(**options, &block)
 		end
+
+		def self.hardware_concurrency
+			Etc.nprocessors
+		rescue
+			2
+		end
 	end
 end

lib/async/container/version.rb

@@ -20,6 +20,6 @@
 
 module Async
 	module Container
-		VERSION = "0.2.2"
+		VERSION = "0.3.0"
 	end
 end

spec/async/container_spec.rb

@@ -32,4 +32,8 @@
 
 		expect(count).to be == 1
 	end
+
+	it "can get hardware concurrency" do
+		expect(Async::Container.hardware_concurrency).to be >= 1
+	end
 end