The Linux implementation allocates an array of native utf8 strings that are null terminated when mapping managed env vars to native env vars:

We should detect the case when ProcessStartOptions.HasEnvironmentBeenAccessed returns false and do the following:

• don't access ProcessStartOptions.Environment to avoid allocations
• don't allocate the native memory here:

  ProcessPlayground/Library/SafeChildProcessHandle.Linux.cs

  Line 125 in b361571

  UnixHelpers.AllocNullTerminatedArray(envp, ref envpPtr);

• just pass null to the native layer and make it pass environ directly to execve.

By doing that we are going to avoid needles utf8->unicode->utf8 converstion for all the env vars in case where user has not modified the env vars and the process should simply derive the env vars from parent.