Macro dispatch_sink_formatter_str_key_impl

macro_rules! dispatch_sink_formatter_str_key_impl {
    ($impl:expr, $name:ident, $body:expr) => { ... };
}

Macro to dispatch formatting implementation for sink formatters that require string keys. Used when the message key must be a string (excludes some Avro and bytes implementations).

Similar to dispatch_sink_formatter_impl, but excludes certain formatter types that don’t support string keys (e.g., AppendOnlyAvro, UpsertAvro). These cases are marked as unreachable!() since they should never occur in contexts requiring string keys.