public Builder clearTtl() {
      bitField0_ = (bitField0_ & ~0x00000002);
      ttl_ = null;
      if (ttlBuilder_ != null) {
        ttlBuilder_.dispose();
        ttlBuilder_ = null;
      }
      onChanged();
      return this;
    }
<pre>
Optional. TTL for the backup to expire. Value range is 1 day to 100 years.
If not specified, the default value is 100 years.
</pre>

<code>.google.protobuf.Duration ttl = 2 [(.google.api.field_behavior) = OPTIONAL];</code>
java-valkey/proto-google-cloud-valkey-v1/src/main/java/com/google/cloud/memorystore/v1/BackupInstanceRequest.java