clearVersion method Null safety

1. printersdk
2. printer.pb
3. UsbDevice
4. clearVersion method

UsbDevice class

1. Constructors
2. UsbDevice
3. fromBuffer
4. fromJson
5. Properties
6. eventPlugin
7. hashCode
8. info_
9. isFrozen
10. mainClass
11. manufactureName
12. name
13. productId
14. productName
15. runtimeType
16. subClass
17. type
18. unknownFields
19. vendorId
20. version
21. Methods
22. $_ensure
23. $_get
24. $_getB
25. $_getBF
26. $_getI
27. $_getI64
28. $_getIZ
29. $_getList
30. $_getMap
31. $_getN
32. $_getS
33. $_getSZ
34. $_has
35. $_setBool
36. $_setBytes
37. $_setDouble
38. $_setFloat
39. $_setInt64
40. $_setSignedInt32
41. $_setString
42. $_setUnsignedInt32
43. $_whichOneof
44. addExtension
45. check
46. clear
47. clearExtension
48. clearField
49. clearMainClass
50. clearManufactureName
51. clearName
52. clearProductId
53. clearProductName
54. clearSubClass
55. clearType
56. clearVendorId
57. clearVersion
58. clone
59. copyWith
60. createEmptyInstance
61. createMapField
62. createRepeatedField
63. ensureType
64. extensionsAreInitialized
65. freeze
66. getDefaultForField
67. getExtension
68. getField
69. getFieldOrNull
70. getTagNumber
71. hasExtension
72. hasField
73. hasMainClass
74. hasManufactureName
75. hasName
76. hasProductId
77. hasProductName
78. hasRequiredFields
79. hasSubClass
80. hasType
81. hasVendorId
82. hasVersion
83. isInitialized
84. mergeFromBuffer
85. mergeFromCodedBufferReader
86. mergeFromJson
87. mergeFromJsonMap
88. mergeFromMessage
89. mergeFromProto3Json
90. mergeUnknownFields
91. noSuchMethod
92. setExtension
93. setField
94. toBuilder
95. toDebugString
96. toProto3Json
97. toString
98. writeToBuffer
99. writeToCodedBufferWriter
100. writeToJson
101. writeToJsonMap
102. Operators
103. operator ==
104. Static methods
105. create
106. createRepeated
107. getDefault