Number,Description,Reference
0,Unrecognized Critical Record,"[RFC8915, Section 4.1.3]"
1,Bad Request,"[RFC8915, Section 4.1.3]"
2,Internal Server Error,"[RFC8915, Section 4.1.3]"
3-32767,Unassigned,
32768-65535,Reserved for Private or Experimental Use,[RFC8915]