Steps to reproduce:
1. Download attached project
2. Build a standalone player with IL2CPP backend
3. Navigate to C:\Users\[USERNAME]\AppData\LocalLow\DefaultCompany\pipetest\output_log.txt

Actual results: Notice that the exception is printed.

Reproduced with: 2019.3.0a5, 2019.2.0b5, 2019.1.5f1, 2018.4.1f1
Not reproducible with: 2018.3.0a5
Regression introduced in: 2018.3.0a6

NotImplementedException: The method or operation is not implemented.
at System.IO.Pipes.NamedPipeClientStream..ctor (System.String serverName, System.String pipeName, System.IO.Pipes.PipeDirection direction, System.IO.Pipes.PipeOptions options, System.Security.Principal.TokenImpersonationLevel impersonationLevel, System.IO.HandleInheritability inheritability) [0x00000] in <00000000000000000000000000000000>:0
at System.IO.Pipes.NamedPipeClientStream..ctor (System.String serverName, System.String pipeName, System.IO.Pipes.PipeDirection direction, System.IO.Pipes.PipeOptions options, System.Security.Principal.TokenImpersonationLevel impersonationLevel) [0x00000] in <00000000000000000000000000000000>:0
at System.IO.Pipes.NamedPipeClientStream..ctor (System.String serverName, System.String pipeName, System.IO.Pipes.PipeDirection direction, System.IO.Pipes.PipeOptions options) [0x00000] in <00000000000000000000000000000000>:0
at MainCode.Start () [0x00000] in <00000000000000000000000000000000>:0

Note:
- not reproducible on mono backend

Fixed in: 2018.4.4f1, 2019.1.9f1, 2019.2.1f1, 2019.3.0a11