public com.google.protobuf.ByteString getBootDiskTypeBytes() {
      java.lang.Object ref = bootDiskType_;
      if (ref instanceof String) {
        com.google.protobuf.ByteString b =
            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
        bootDiskType_ = b;
        return b;
      } else {
        return (com.google.protobuf.ByteString) ref;
      }
    }
<pre>
Type of the boot disk (default is "pd-ssd").
Valid values: "pd-ssd" (Persistent Disk Solid State Drive) or
"pd-standard" (Persistent Disk Hard Disk Drive).
</pre>

<code>string boot_disk_type = 1;</code>

@return The bytes for bootDiskType.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/DiskSpec.java