Add streams to proc arguments, use requestStream

This makes functions look just like in actual libvirt API, except
virStreamPtr is replaced with io.Reader for outgoing streams and
io.Writer for incoming streams.

internal/lvgen/procedures.tmpl

@@ -23,6 +23,7 @@ package libvirt
 import (
 	"bytes"
 	"fmt"
+	"io"
 
 	"github.com/davecgh/go-xdr/xdr2"
 	"github.com/digitalocean/go-libvirt/internal/constants"
@@ -126,9 +127,15 @@ func decodeTypedParams(dec *xdr.Decoder) ([]TypedParam, error) {
 	return params, nil
 }
 
-{{range .Procs}}
+{{range $proc := .Procs}}
 // {{.Name}} is the go wrapper for {{.LVName}}.
-func (l *Libvirt) {{.Name}}({{range $ix, $arg := .Args}}{{if $ix}}, {{end}}{{.Name}} {{.Type}}{{end}}) ({{range .Ret}}r{{.Name}} {{.Type}}, {{end}}err error) {
+func (l *Libvirt) {{.Name}}(
+  {{- range $ix, $arg := .Args}}
+    {{- if (eq $ix $proc.WriteStreamIdx)}}{{if $ix}}, {{end}}outStream io.Reader{{end}}
+    {{- if (eq $ix $proc.ReadStreamIdx)}}{{if $ix}}, {{end}}inStream io.Writer{{end}}
+    {{- if $ix}}, {{end}}{{.Name}} {{.Type}}
+  {{- end -}}
+) ({{range .Ret}}r{{.Name}} {{.Type}}, {{end}}err error) {
 	var buf []byte
 {{if .ArgsStruct}}
 	args := {{.ArgsStruct}} {
@@ -141,7 +148,10 @@ func (l *Libvirt) {{.Name}}({{range $ix, $arg := .Args}}{{if $ix}}, {{end}}{{.Na
 	}
 {{end}}
 {{if .RetStruct}}	var r response{{end}}
-	{{if .RetStruct}}r{{else}}_{{end}}, err = l.request({{.Num}}, constants.Program, buf)
+	{{if .RetStruct}}r{{else}}_{{end}}, err = l.requestStream({{.Num}}, constants.Program, buf,
+    {{- if (ne .WriteStreamIdx -1)}} outStream,{{else}} nil,{{end}}
+    {{- if (ne .ReadStreamIdx -1)}} inStream{{else}} nil{{end -}}
+    )
 	if err != nil {
 		return
 	}