Core occasionally cannot be down

在国内pod realm时，有时连了蓝灯也会遇到下面这个问题：

[!] /bin/bash -c

set -e

sh build.sh cocoapods-setup

core is not a symlink. Deleting...

Downloading dependency: core 0.96.1

Downloading core failed:

curl: (56) SSLRead() return error -9806

Core occasionally cannot be downloaded from China #2713

方法一：

rm -rf ~/Library/Caches/CocoaPods/Pods/**/Realm*

rm -rf /Pods

pod install --verbose

方法二：

1、编辑对应core版本的下载链接(开启vpn或者蓝灯)：

https://static.realm.io/downloads/sync/realm-sync-cocoa-${REALM_SYNC_VERSION}.tar.xz

${REALM_SYNC_VERSION}：core的版本号

2、cd `getconf DARWIN_USER_TEMP_DIR`

3.curl https://static.realm.io/downloads/core/realm-core-1.3.0.tar.bz2 -o realm-core-1.3.0.tar.bz2

(use VPN or use the website to help download on onedrive: http://ctrlq.org/save/)

4、到工程的Podfile路径下执行：pod install --verbose