@Test void writeAscii_long() {
    assertThat(writeAscii(-1005656679588439279L))
      .isEqualTo("-1005656679588439279");
    assertThat(writeAscii(0L))
      .isEqualTo("0");
    assertThat(writeAscii(-9223372036854775808L /* Long.MIN_VALUE */))
      .isEqualTo("-9223372036854775808");
    assertThat(writeAscii(123456789L))
      .isEqualTo("123456789");
  }
Uses test data and codepoint wrapping trick from okhttp3.FormBodyTest
zipkin/src/test/java/zipkin2/internal/WriteBufferTest.java