Flush the global RPC server cache, and tell the rpc server that we've
    reached the given block height at the given time.

def rpc_chain_sync(server_state, new_block_height, finish_time):
    """
    Flush the global RPC server cache, and tell the rpc server that we've
    reached the given block height at the given time.
    """
    rpc_srv = server_state['rpc']
    if rpc_srv is not None:
        rpc_srv.cache_flush()
        rpc_srv.set_last_index_time(finish_time)