How can I transmit the complex data to client

All data that flows between the client and the server is a stream of bits. TCP/IP essentially guarantees that the bits that I send to you get received just like I sent them. That is true in either direction (server<->client, client<->server) once the connection is established.

Any data that is sent between the client and the server is done as per an agreed to protocol. The protocol typically assumes that not a single "bit"--NOTHING will be lost in this end to end transmission. This is part of the TCP/IP guarantee. Basically, you will get the text message verbatim as I sent it.