Update doc/contributing/erm-guidelines.md

Co-authored-by: René <[email protected]>

Author: jasnell

doc/contributing/erm-guidelines.md

@@ -132,7 +132,13 @@ So with this is mind, it is necessary to outline some guidelines for disposers:
    criteria is not met, then the disposer is actually a synchronous disposer in
    disguise, and will block the execution thread until it returns; such a
    disposer should instead be declared using `Symbol.dispose`.
-7. Avoid, as much as possible, using both `Symbol.dispose` and `Symbl.asyncDispose`
+7. Because the disposal process is strictly ordered, there is an intrinsic
+   expectation that all tasks performed by a single disposer are fully complete
+   at the point that the disposer returns. This means, for example, that
+   "callback-style" APIs must not be invoked within a disposer, unless they are
+   promisified and awaited. Any Promise created within a disposer must be
+   awaited, to ensure its resolution prior to the disposer returning.
+8. Avoid, as much as possible, using both `Symbol.dispose` and `Symbol.asyncDispose`
    in the same object. This can make it difficult to reason about which method
    will be called in a given context and could lead to unexpected behavior or
    subtle bugs. This is not a firm rule, however. Sometimes it may make sense