Module forward 

Forwarding by construction for Source and Sink wrappers (RFC 0013, #877).

A wrapper (a decorator that holds an inner source or sink) must forward every defaulted hook, or the hook silently reverts to its trait default for everything behind the wrapper — exactly-once, upsert, the columnar fast path, multi-table routing. forward_source! and forward_sink! generate the forwarding body for every hook, so a wrapper writes only the methods it changes and a hook added to the trait later reaches the inner connector without touching the wrapper.

Both macros are invoked inside the wrapper’s impl block (with or without #[async_trait]):

forward_sink!(inner);                                  // forward everything
forward_sink!(inner; except write_batch, flush);       // the wrapper defines these

inner names the field holding the wrapped connector: any type whose methods resolve to a Source/Sink (a Box<dyn Sink>, an Arc<S>, a &'a S, a concrete connector), or a tuple index such as 0.

Every hook listed after except is left out: the wrapper either defines it itself or deliberately takes the trait default. A name that is not a hook of the trait is a compile error, and defining a hook without listing it is a duplicate-definition error, so the list stays exact.

Forwarding is verbatim, including the convenience hooks whose default delegates to another hook (fetch_all, stream_pages, check, write_batch_partial, write_batch_idempotent, …). A wrapper that changes a hook must also list the hooks that should go through its change rather than straight to the inner connector — a sink that rewrites records in write_batch lists write_batch_partial, write_batch_idempotent, write_batch_columnar and load_native too. faucet-conformance’s assert_source_forwards_every_hook / assert_sink_forwards_every_hook check the result.