BB     00   Skip over this Option and continue processing.                    
                                                                                
  C       1   Option Data can change en route to the packet's final             
              destination.                                                      
                                                                                
  TTTTT 10000 Option Type assigned from IANA [IANA-HBH].                        
                                                                                
  Length:  4  The size of the value field in Option Data                        
              field supports PMTU values from 0 to 65,534
              octets, the maximum size represented by the
	      Path MTU Option.                              
                                                                                
                                                                                
  Min-PMTU: n 16-bits.  The minimum MTU recorded along the path                 
              in octets, reflecting the smallest link MTU that                  
              the packet experienced along the path.                            
              A value less than the IPv6 minimum link                           
              MTU [RFC8200] MUST be ignored.                                    
                                                                                
  Rtn-PMTU: n 15-bits.  The returned Path MTU field, carrying the 15            
              most significant bits of the latest received Min-PMTU             
              field for the forward path.  The value zero means that            
              no Reported MTU is being returned.                                
                                                                                
  R        n  1-bit.  R-Flag.   Set by the source to signal that                
              the destination host should include the received                  
              Rtn-PMTU field updated by the reported Min-PMTU value             
              when the destination host is to send a PMTU Option back           
              to the source host.