Everything in ABAP

BUSL-1.1 rather than node-rfc's Apache-2.0, so a product you distribute has to be read against the licence and its Additional Use Grant first, and the source is closed: the GitHub repository is the issue tracker and the documentation, nothing else. `RfcServerOptions.bgRfcHandlers` raises instead of accepting handlers, so a server receiving inbound bgRFC units is outside what this does. An ABAP `MESSAGE`-raised failure still arrives with its T100 template rather than the rendered sentence, and the dump name is not reported as `key` for that case.