Move pgproto3 to subdirectory

pgproto3/chunkreader.go

@@ -0,0 +1,19 @@
+package pgproto3
+
+import (
+	"io"
+
+	"github.com/jackc/chunkreader/v2"
+)
+
+// ChunkReader is an interface to decouple github.com/jackc/chunkreader from this package.
+type ChunkReader interface {
+	// Next returns buf filled with the next n bytes. If an error (including a partial read) occurs,
+	// buf must be nil. Next must preserve any partially read data. Next must not reuse buf.
+	Next(n int) (buf []byte, err error)
+}
+
+// NewChunkReader creates and returns a new default ChunkReader.
+func NewChunkReader(r io.Reader) ChunkReader {
+	return chunkreader.New(r)
+}