NewID returns a new ID using pkg for the PkgPath, strct for the Struct, and field for the Field.

NewIndex returns a new empty Index.

NewOffsets returns a new empty *Offsets.

ID is a struct field identifier for an offset.

Index holds all struct field offsets.

OffsetKey is the offset of a specific struct field in a specific version.

Offsets are the byte offsets for a struct field at specific versions of the package containing struct.