src/main/java/io/github/glytching/junit/extension/util/ExtensionUtil.java
public static ExtensionContext.Store getStore(ExtensionContext extensionContext, Class clazz) {
    return extensionContext.getStore(namespace(extensionContext, clazz));
  }
public static ExtensionContext.Store getStore(ExtensionContext extensionContext, Class clazz) {
    return extensionContext.getStore(namespace(extensionContext, clazz));
  }
Creates a {@link ExtensionContext.Store} for a given {@code extensionContext}. A {@link
ExtensionContext.Store} is bound to an {@link ExtensionContext} so different test invocations
do not share the same store. For example a test invocation on {@code ClassA.testMethodA} will
have a different {@link ExtensionContext.Store} instance to that associated with a test
invocation on {@code ClassA.testMethodB} or test invocation on {@code ClassC.testMethodC}.

@param extensionContext the <em>context</em> in which the current test or container is being
executed
@return a {@link ExtensionContext.Store} for the given {@code extensionContext}