@java.lang.Override
        public void writeTo(com.google.protobuf.CodedOutputStream output)
                throws java.io.IOException {
            if (!com.google.protobuf.GeneratedMessage.isStringEmpty(url_)) {
                com.google.protobuf.GeneratedMessage.writeString(output, 1, url_);
            }
            if (((bitField0_ & 0x00000001) != 0)) {
                output.writeInt32(2, duration_);
            }
            if (((bitField0_ & 0x00000002) != 0)) {
                output.writeInt32(3, size_);
            }
            if (((bitField0_ & 0x00000004) != 0)) {
                com.google.protobuf.GeneratedMessage.writeString(output, 4, format_);
            }
            getUnknownFields().writeTo(output);
        }
<code>optional string format = 4;</code>

@return The bytes for format.
turms-server-common/src/main/java/im/turms/server/common/access/client/dto/model/file/VideoFile.java