Updating issue field value with type 'any' fails

[cholin-bmc]

For an issue, try to set the 'Epic' field which is customfield_10009

"customfield_10009": {
  "required": false,
  "schema": {
    "type": "any",
    "custom": "com.pyxis.greenhopper.jira:gh-epic-link",
    "customId": 10009
  },
  "name": "Epic Link",
  "key": "customfield_10009",
  "operations": [
    "set"
  ]
},

Custom field metadata was obtained from https://somename.atlassian.net/rest/api/2/issue/SAMPLE-2/editmeta

The below code is able to retrieve an issue's epic, but not set it:

            Issue issue = jira.getIssue("SAMPLE-2");

            def epic = issue.getField('customfield_10009')
            println "issue's epic: ${epic}"

            issue.update()
                    .field('customfield_10009', 'SAMPLE-4')
                    .execute()

The update throws the following exception:

Caused by: java.lang.UnsupportedOperationException: any is not a supported field type
	at net.rcarz.jiraclient.Field.toJson(Field.java:738)
	at net.rcarz.jiraclient.Issue$FluentUpdate.execute(Issue.java:355)