@Test void field_readLengthPrefixAndValue_LENGTH_DELIMITED_truncated() {
    BytesField field = new BytesField(128 << 3 | WIRETYPE_LENGTH_DELIMITED);
    bytes = new byte[10];
    WriteBuffer.wrap(bytes).writeVarint(100); // much larger than the buffer size

    try {
      field.readLengthPrefixAndValue(ReadBuffer.wrap(bytes));
      failBecauseExceptionWasNotThrown(IllegalArgumentException.class);
    } catch (IllegalArgumentException e) {
      assertThat(e).hasMessage("Truncated: length 100 > bytes available 9");
    }
  }
Shows we can reliably look at a byte zero to tell if we are decoding proto3 repeated fields.
zipkin/src/test/java/zipkin2/internal/Proto3FieldsTest.java