net: merge two versions of SetTCPNoDelay() function into one

net/tools/flip_server/tcp_socket_util.h

Index: net/tools/flip_server/tcp_socket_util.h
diff --git a/net/tools/flip_server/tcp_socket_util.h b/net/tools/flip_server/tcp_socket_util.h
index cbd35e7260c6398a040168bcf17b6809f8cc8529..4e2e910ef431126a3af2380fa573f917ff5ec244 100644
--- a/net/tools/flip_server/tcp_socket_util.h
+++ b/net/tools/flip_server/tcp_socket_util.h
@@ -9,14 +9,6 @@
 
 namespace net {
 
-// This function disables buffering in the kernel. By default, TCP sockets
-// will wait up to 200ms for more data to complete a packet before transmitting.
-// After calling this function, the kernel will not wait. See TCP_NODELAY in
-// `man 7 tcp`.
-// This function returns true if it succeeds to set the TCP_NODELAY option,
-// otherwise returns false.
-bool SetTCPNoDelay(int fd);
-
 // Summary:
 //   creates a socket for listening, and bind()s and listen()s it.
 // Args: