Module primitives 

Key types shared across multiple sui-rpc-store CFs.

Keys used by only one CF live in that CF’s own module; only the types reused across many CFs land here.

Structs

StructTagKey

Newtype wrapping StructTag with a streaming-friendly Encode / Decode pair.

TypeTagKey

Newtype wrapping TypeTag with the same byte-identical, but streaming-friendly Encode / Decode shape as StructTagKey.

U64Be

A u64 encoded big-endian, suitable for keys whose iteration order should match numerical order. Shared across CFs keyed by transaction sequence, checkpoint sequence, and epoch id, and reused as the value type for the tx_seq_by_digest and checkpoint_seq_by_digest lookup CFs.

U64Varint

A u64 encoded as a protobuf-style varint, suitable for value positions where on-disk size matters more than sort order. Compared to U64Be: smaller for typical values (1–5 bytes for anything below 2^35), slightly larger only near the u64::MAX corner (up to 10 bytes), and never sort-stable — hence values only.

UnitKey

Zero-byte key for singleton CFs. Encodes as the empty byte string; decoding requires the input to be empty too.