Major - P3 mongocryptd currently only writes a single integer as a string to its pid file. Drivers need to more information to use mongocryptd as a singleton process.
Mongocryptd needs to write the following information as JSON to its pid file:
{
port : <int>
domainSocket: <string> # Not present on Windows
pid : <int>
}
port - is the port that mongocryptd is running on
pid - is the process number of mongocryptd
domainSocket - path to unix domain socket, not present on Windows