feat: use lsof for net_connections on FreeBSD

Use net.ConnectionsPidWithContext on FreeBSD, similarly to how it is done
on Darwin. This uses common.CallLsofWithContext underneath the hood, which
will use lsof under the hood, if available.

Tested on FreeBSD 13.2-RELEASE

Signed-off-by: Chris Gianelloni <wolf31o2@blinklabs.io>

README.md

@@ -190,7 +190,7 @@ Some code is ported from Ohai. Many thanks.
 |users                 |x      |x        |x        |x       |x        |         |         |
 |pids                  |x      |x        |x        |x       |x        |         |         |
 |pid\_exists           |x      |x        |x        |x       |x        |         |         |
-|net\_connections      |x      |         |x        |x       |         |         |         |
+|net\_connections      |x      |x        |x        |x       |         |         |         |
 |net\_protocols        |x      |         |         |        |         |         |         |
 |net\_if\_addrs        |       |         |         |        |         |         |         |
 |net\_if\_stats        |       |         |         |        |         |         |         |

process/process_freebsd.go

@@ -286,11 +286,11 @@ func (p *Process) ChildrenWithContext(ctx context.Context) ([]*Process, error) {
 }
 
 func (p *Process) ConnectionsWithContext(ctx context.Context) ([]net.ConnectionStat, error) {
-	return nil, common.ErrNotImplementedError
+	return net.ConnectionsPidWithContext(ctx, "all", p.Pid)
 }
 
 func (p *Process) ConnectionsMaxWithContext(ctx context.Context, max int) ([]net.ConnectionStat, error) {
-	return nil, common.ErrNotImplementedError
+	return net.ConnectionsPidMaxWithContext(ctx, "all", p.Pid, max)
 }
 
 func ProcessesWithContext(ctx context.Context) ([]*Process, error) {