class FDB::FutureKeyArray

def wait
  block_until_ready
  ks = FFI::MemoryPointer.new :pointer
  count = FFI::MemoryPointer.new :int
  FDBC.check_error FDBC.fdb_future_get_key_array(@fpointer, kvs, count)
  ks = ks.read_pointer
  (0..count.read_int-1).map{|i|
    x = FDBC::KeyStruct.new(ks + (i * FDBC::KeyStruct.size))
    x[:key].read_bytes(x[:key_length])
   }
end