There has been a change to the HTTPRIO.HTTPWebNode.OnBeforePost event in Delphi 10.3.

Before Delphi 10.3, the event handler was defined this way, and it worked perfectly:

procedure TForm1.HTTPRIO1HTTPWebNode1BeforePost(const HTTPReqResp: THTTPReqResp;
  Data: Pointer);
var
  auth: String;
begin
  auth := 'Authorization: Basic ' + IdEncoderMIME1.EncodeString('user:password');
  HttpAddRequestHeaders(Data, PChar(auth), Length(auth), HTTP_ADDREQ_FLAG_ADD);
end;

In Delphi 10.3, the Data parameter is gone, instead a THTTPClient is given, and I have no idea how to implement Basic authentication with it:

procedure TForm1.HTTPRIO1HTTPWebNode1BeforePost(const HTTPReqResp: THTTPReqResp;
  Client: THTTPClient);
var
  auth: String;
begin
  auth := 'Authorization: Basic ' + IdEncoderMIME1.EncodeString('user:password');
  ???
end;

Any hints?