# Functions
NewFSMetadataStore creates a new filesystem-based metadata store.
NewV1IDService creates a new V1 ID mapping service.
NewV2MetadataService creates a new diff ID to v2 metadata mapping service.
# Structs
FSMetadataStore uses the filesystem to associate metadata with layer and image IDs.
V1IDService maps v1 IDs to layers on disk.
V2Metadata contains the digest and source repository information for a layer.
V2MetadataService maps layer IDs to a set of known metadata for the layer.
# Interfaces
Store implements a K/V store for mapping distribution-related IDs to on-disk layer IDs and image IDs.