升级OS10.12之后，react-native的本地服务突然不能正常启动了。怀疑是react-native版本问题。从0.28.x的版本切换到0.33.x的版本，还是不能启动，报错如下：
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
ERROR watch null EMFILE
{"code":"EMFILE","errno":"EMFILE","syscall":"watch null","filename":null}
Error: watch null EMFILE
at exports._errnoException (util.js:890:11)
at FSEvent.FSWatcher._handle.onchange (fs.js:1296:21)

修复方法：升级watchman版本至4.6
We were able to get it to work by increasing the max file limit and moving to watchman v4.6.0
here are the steps we followed:

1. increase max file limt

   check open file limit

   sysctl kern.maxfiles

   edit sysctl

   sudo vim /etc/sysctl.conf

   add these two lines

   kern.maxfiles=10485760
   kern.maxfilesperproc=1048576

   reboot

   sudo reboot

   check new file limit

   sysctl kern.maxfiles

2. upgrade to watchman 4.6

   clone repo

   git clone https://github.com/facebook/watchman.git

   change to master branch

   git checkout -b v4.6.0 v4.6.0

   run compiler

   ./autogen.sh
   ./configure --enable-lenient --without-pcre --with-python
   make
   sudo make install

   check watchman version

   watchman -v

   result should be 4.6.0

   其中1步骤失败了。2的步骤成功。
   可以启动本地服务器了。

解决方法：https://github.com/facebook/react-native/issues/9309