Revert "Add new TCPBufferSize parameter to network"

This reverts commit 57cb1b5aa0.

network/init_test.go

@@ -30,10 +30,6 @@ func (d *DialerMock) DialContext(ctx context.Context, network, address string) (
 	return args.Get(0).(net.Conn), args.Error(1)
 }
 
-func (d *DialerMock) TCPBufferSize() int {
-	return d.Called().Int(0)
-}
-
 type HTTPServerTestSuite struct {
 	httpServer *httptest.Server
 }