ServerOptions.ProcessEnvironment

ProcessEnvironment replaces the child process environment. Nil snapshots the current process environment. A non-nil empty slice supplies no caller-provided variables. Execution may add variables required by Go's target platform and a canonical TMUX_TMPDIR that freezes named or default socket selection. Duplicate names retain their last value. Entries containing NUL are rejected except on Plan 9, where NUL separates path-list elements. NewServer clones the slice.