下载Dart SDK

Dart的官方页面，只给了一个拼凑下载地址的说明，没有给出具体的链接，这里统一列出来好了

Mac平台

32位下载地址：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-macos-ia32-release.zip

64位下载地址：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-macos-x64-release.zip

文档地址：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/api-docs/dartdocs-gen-api.zip

Windows平台

32位：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-windows-ia32-release.zip

64位：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-windows-x64-release.zip

文档：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/api-docs/dartdocs-gen-api.zip

Linux平台

32位：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-linux-ia32-release.zip

64位：
https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-linux-x64-release.zip

ARM V7

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-linux-arm-release.zip

ARMv8 (ARM64):

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/sdk/dartsdk-linux-arm64-release.zip

文档：

https://storage.googleapis.com/dart-archive/channels/stable/release/2.4.0/api-docs/dartdocs-gen-api.zip