Rollup merge of #67313 - oli-obk:document_all_the_t̶h̶i̶n̶g̶s̶dataflow, r=ecstatic-morse
Rollup merge of #67313 - oli-obk:document_all_the_t̶h̶i̶n̶g̶s̶dataflow, r=ecstatic-morse

Document more use cases of dataflow

r? @ecstatic-morse

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust