C:\Users\Sean\Documents\ArduinoData\packages\arduino\hardware\avr1円.8.1\libraries\Wire\src\utility\twi.c: In function '__vector_24':
C:\Users\Sean\Documents\ArduinoData\packages\arduino\hardware\avr1円.8.1\libraries\Wire\src\utility\twi.c:447:49: warning: this statement may fall through [-Wimplicit-fallthrough=]
 twi_masterBuffer[twi_masterBufferIndex++] = TWDR;
 ^
C:\Users\Sean\Documents\ArduinoData\packages\arduino\hardware\avr1円.8.1\libraries\Wire\src\utility\twi.c:448:5: note: here
 case TW_MR_SLA_ACK: // address sent, ack received
 ^~~~
C:\Users\Sean\Documents\ArduinoData\packages\arduino\hardware\avr1円.8.1\libraries\Wire\src\utility\twi.c:529:9: warning: this statement may fall through [-Wimplicit-fallthrough=]
 if(0 == twi_txBufferLength){
 ^
C:\Users\Sean\Documents\ArduinoData\packages\arduino\hardware\avr1円.8.1\libraries\Wire\src\utility\twi.c:534:5: note: here
 case TW_ST_DATA_ACK: // byte sent, ack returned
 ^~~~