更新说明文档

README.md

-# librf
+# librf 2.0
 
 ### librf  - 协程库
 
+2020-02-16 更新：
+    更新调度器算法，深入应用Coroutines的特性，以期获得更高调度性能。
+    不再支持C++14。
+
 librf是一个基于C++ Coroutines提案 ‘Stackless Resumable Functions’编写的非对称stackless协程库。
 
 目前仅支持:
 
-    Windows (使用VS2015/2017编译)
+    Windows (使用VS2017/VS2019编译)
 
 
 librf有以下特点：

librf/src/sleep.cpp

 
 		return awaitable.get_future();
 	}
-}
+}

vs_proj/librf.vcxproj

   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
-    <PlatformToolset>v142</PlatformToolset>
+    <PlatformToolset>v141</PlatformToolset>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>NotSet</CharacterSet>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
-    <PlatformToolset>v142</PlatformToolset>
+    <PlatformToolset>v141</PlatformToolset>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>NotSet</CharacterSet>
   </PropertyGroup>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <AdditionalOptions>/await</AdditionalOptions>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
-      <LanguageStandard>stdcpplatest</LanguageStandard>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <AdditionalOptions>/await</AdditionalOptions>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
-      <LanguageStandard>stdcpplatest</LanguageStandard>
+      <LanguageStandard>stdcpp17</LanguageStandard>
       <MinimalRebuild />
       <CLanguageStandard>c11</CLanguageStandard>
       <CppLanguageStandard>c++1y</CppLanguageStandard>
       <AdditionalIncludeDirectories>..\librf;..\..\asio\asio\include;..\..\asio-1.10.6\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <AdditionalOptions>/await</AdditionalOptions>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
-      <LanguageStandard>stdcpplatest</LanguageStandard>
+      <LanguageStandard>stdcpp17</LanguageStandard>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <InlineFunctionExpansion>AnySuitable</InlineFunctionExpansion>
       <EnableFiberSafeOptimizations>true</EnableFiberSafeOptimizations>
       <OmitFramePointers>true</OmitFramePointers>
       <EnableFiberSafeOptimizations>true</EnableFiberSafeOptimizations>
       <StringPooling>true</StringPooling>
-      <LanguageStandard>stdcpplatest</LanguageStandard>
+      <LanguageStandard>stdcpp17</LanguageStandard>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <SDLCheck>