Create a chain of DafReaders with a final DafWriter.
Examples
base <- memory_daf(name = "base")
add_axis(base, "cell", c("c1", "c2"))
writable <- memory_daf(name = "writable")
ch <- chain_writer(list(base, writable))
set_scalar(ch, "organism", "human")
get_scalar(ch, "organism")
#> [1] "human"