chore: Move private packages to internal (#1664)

internal/perfdata/error.go

@@ -0,0 +1,18 @@
+package perfdata
+
+// Error represents error returned from Performance Counters API.
+type Error struct {
+	ErrorCode uint32
+	errorText string
+}
+
+func (m *Error) Error() string {
+	return m.errorText
+}
+
+func NewPdhError(code uint32) error {
+	return &Error{
+		ErrorCode: code,
+		errorText: PdhFormatError(code),
+	}
+}