@Test
public void testGetKey() {
  Context.Key<Span> key = OpenTracingContextKey.getKey();
  assertEquals("Key should have correct name", key.toString(), (OpenTracingContextKey.KEY_NAME));
}
 

@Test
public void testGetSpanContextKey() {
  Key<SpanContext> key = OpenTracingContextKey.getSpanContextKey();
  assertEquals(
      "Key should have correct name", key.toString(), OpenTracingContextKey.KEY_CONTEXT_NAME);
}
 

public GrpcSpanContextHandler(Key<SpanContext> contextKey) {
  this.contextKey = contextKey;
}