public com.google.protobuf.ByteString getFilterBytes() {
        java.lang.Object ref = filter_;
        if (ref instanceof String) {
          com.google.protobuf.ByteString b =
              com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
          filter_ = b;
          return b;
        } else {
          return (com.google.protobuf.ByteString) ref;
        }
      }
<pre>
An optional list of query parameters specified as JSON text in the
form of:

`{"agentPoolNames":["agentpool1","agentpool2",...]}`

Since `agentPoolNames` support multiple values, its values must be
specified with array notation. When the filter is either empty or not
provided, the list returns all agent pools for the project.
</pre>

<code>string filter = 2;</code>

@return The bytes for filter.
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferProto.java