@Test void writeString() {
    StringBuilder builder = new StringBuilder();
    for (int i = 0; i < 100000; i++) {
      builder.append("a");
    }
    String string = builder.toString();
    byte[] bytes = new byte[string.length()];
    WriteBuffer.wrap(bytes).writeAscii(string);
    assertThat(new String(bytes, UTF_8)).isEqualTo(string);
  }
Uses test data and codepoint wrapping trick from okhttp3.FormBodyTest
zipkin/src/test/java/zipkin2/internal/WriteBufferTest.java