Tag { public final String key() { return key; } protected  Tag(String key); final String key(); @Nullable String value(@Nullable I input, @Nullable TraceContext context); final void tag(I input, ScopedSpan span); final void tag(I input, Span span); final void tag(I input, @Nullable TraceContext context, SpanCustomizer span); final void tag(I input, SpanCustomizer span); final void tag(I input, @Nullable TraceContext context, MutableSpan span); @Override String toString();  }
@Test public void trimsKey() { assertThat(new Tag<Object>(" x-foo ") { @Override protected String parseValue(Object input, TraceContext context) { return null; } }.key()).isEqualTo("x-foo"); }