public Builder clearStartTime() {
        bitField0_ = (bitField0_ & ~0x00000001);
        startTime_ = null;
        if (startTimeBuilder_ != null) {
          startTimeBuilder_.dispose();
          startTimeBuilder_ = null;
        }
        onChanged();
        return this;
      }
<pre>
Start time of the partition.
</pre>

<code>.google.protobuf.Timestamp start_time = 1;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/Partition.java