[#246] pkg/client: Use io.Reader wrapper at object put

Object payload transferred in chunks. Size of the
chunks may be limited by transport protocols. To
split it we use `io.CopyBuffer` with pre-allocated
buffer size of one chunk. However this function may
ignore buffer if reader or writer implements
`WriteTo` or `ReadFrom` methods. Unfortunately
`bytes.Reader` implements `WriteTo` function.

To fix this we wrap reader so wrapper implements
only `io.Reader` interface.

Related to github.com/nspcc-dev/neofs-node/issues/338

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/client/object.go

@@ -83,6 +83,10 @@ type SearchObjectParams struct {
 	filters object.SearchFilters
 }
 
+type putObjectV2Reader struct {
+	r io.Reader
+}
+
 type putObjectV2Writer struct {
 	key *ecdsa.PrivateKey
 
@@ -134,6 +138,10 @@ func (t checksumType) toV2() v2refs.ChecksumType {
 	}
 }
 
+func (w *putObjectV2Reader) Read(p []byte) (int, error) {
+	return w.r.Read(p)
+}
+
 func (w *putObjectV2Writer) Write(p []byte) (int, error) {
 	w.chunkPart.SetChunk(p)
 
@@ -272,8 +280,10 @@ func (c *Client) putObjectV2(ctx context.Context, p *PutObjectParams, opts ...Ca
 		stream:    stream,
 	}
 
+	r := &putObjectV2Reader{r: rPayload}
+
 	// copy payload from reader to stream writer
-	_, err = io.CopyBuffer(w, rPayload, make([]byte, chunkSize))
+	_, err = io.CopyBuffer(w, r, make([]byte, chunkSize))
 	if err != nil && !errors.Is(errors.Cause(err), io.EOF) {
 		return nil, errors.Wrap(err, "could not send payload bytes to Put object stream")
 	}