Swift 原本的写法：

class test {
  static func someFunctionWithNonescapingClosure(closure: (String) -> Void) {
    let testString: String = "123"
    closure(testString)
  }

  static func usage() {
    someFunctionWithNonescapingClosure { newString in
      print(newString)

    }
  }
}

test.usage()

换 C# 之后：

using System;

class Untitled {
  static void someFunctionWithNonescapingClosure(Action<string> closure) {
    string testString = "123";
    closure(testString);
  }

  static void usage() {
    Action<string> testStr = Console.WriteLine;
    someFunctionWithNonescapingClosure(testStr);
  }
  static void Main(string[] args) { usage(); }
}