type: number
enum:
  # Field type unknown.
  - 0 # TYPE_UNKNOWN
  # Field type double.
  - 1 # TYPE_DOUBLE
  # Field type float.
  - 2 # TYPE_FLOAT
  # Field type int64.
  - 3 # TYPE_INT64
  # Field type uint64.
  - 4 # TYPE_UINT64
  # Field type int32.
  - 5 # TYPE_INT32
  # Field type fixed64.
  - 6 # TYPE_FIXED64
  # Field type fixed32.
  - 7 # TYPE_FIXED32
  # Field type bool.
  - 8 # TYPE_BOOL
  # Field type string.
  - 9 # TYPE_STRING
  # Field type group. Proto2 syntax only, and deprecated.
  - 10 # TYPE_GROUP
  # Field type message.
  - 11 # TYPE_MESSAGE
  # Field type bytes.
  - 12 # TYPE_BYTES
  # Field type uint32.
  - 13 # TYPE_UINT32
  # Field type enum.
  - 14 # TYPE_ENUM
  # Field type sfixed32.
  - 15 # TYPE_SFIXED32
  # Field type sfixed64.
  - 16 # TYPE_SFIXED64
  # Field type sint32.
  - 17 # TYPE_SINT32
  # Field type sint64.
  - 18 # TYPE_SINT64