errors

var (
	// ErrOther indicates that the error is unknown.
	ErrOther = newError(CodeErrOther, "something error")
	// ErrNotFound indicates that the item was not found.
	ErrNotFound = newError(CodeErrNotFound, "the item does not exist")
	// ErrTimedOut indicates that the communication is timed out.
	ErrTimedOut = newError(CodeErrTimedOut, "the operation timed out")
	// ErrAlreadyExists will be occured if the duplicated item is created.
	ErrAlreadyExists = newError(CodeErrAlreadyExists, "the item has already existed")

	// Authentication and Authorization
	// ErrAuthFailed indicates that the authentication was failed.
	// Username or password (or other authentication factor) is wrong.
	ErrAuthFailed = newError(CodeErrAuthFailed, "authentication failed")
	// ErrPermissionDenied indicates that the operation was denied because the user to exec it did not have the enough permission.
	ErrPermissionDenied = newError(CodeErrPermissionDenied, "permission denied")

	// ErrContextCanceled will be occured when the context was canceled.
	ErrContextCanceled = newError(CodeErrContextCanceled, "Context canceled")
)