0.31.2
(internal): Add an internal package, which now contains the internal functionality previously included in the core package (e.g. core.Caller -> internal.Caller).
Although technically a breaking change in terms of the module itself, this change was always the intention, and should have zero impact on users.
Any core type that is meant for public consumption remains in the exported core package (e.g. core.APIError and core.RequestOption).
0.31.1
(internal): Adds additional tests to confirm the behavior of the core.Retrier.
No functional, user-facing changes are included.