Indy 10 IOHandler write block

Hi all,
Is there a command to write a raw block of memory over TCPclient's
IOHandler?
Something similar to file BlockWrite/read
I see Write(ABuffer:TBytes) but how to tell it how many bytes to write, or
must I make a TBytes array, copy into it & then write?

Basically just loking for a way to write raw records or memory blocks
without converting first to stream or whatever.

Thanks
AntonE