// Default parameters

  targetDir = "./"
  port = "29418"

// Usage example
node {
  gitSSHCheckout {
    credentialsId = "mcp-ci-gerrit"
    branch = "mcp-0.1"
    host = "ci.mcp-ci.local"
    project = "projectcalico/calico-containers"
  }
}

// or

node {
  gitSSHCheckout {
    credentialsId = "mcp-ci-gerrit"
    branch = "mcp-0.1"
    host = "ci.mcp-ci.local"
    project = "projectcalico/calico-containers"
    targetDir = "some_directory"
  }
}

// by default if you checkout even to branch you will be in detached mode
// but some tools (e.g. pip) requires "merged" code
// https://issues.jenkins-ci.org/browse/JENKINS-6856
// so you need to use withMerge = true

node {
  gitSSHCheckout {
    credentialsId = "mcp-ci-gerrit"
    branch = "mcp"
    host = "ci.mcp-ci.local"
    project = "projectcalico/calico-containers"
    targetDir = "some_directory"
    withMerge = true
  }
}

Please see example below:
1. withMerge = false (default)
  $ git status
  HEAD detached at 25fd9c2
  nothing to commit, working directory clean
  $ git branch -av
  * (HEAD detached at 25fd9c2)       25fd9c2 Fix .gitreview
    remotes/origin/HEAD              7e2b36e Merge pull request #160 from tomdee/tiny-build-image-size-tweaks
    remotes/origin/develop           013614f Merge pull request #144 from djosborne/comment-etcd-pin
    remotes/origin/feature/utreports 3c52c2a disable usage reports while running unit tests
    remotes/origin/go                350e251 Merge pull request #128 from caseydavenport/ipam-code-review
    remotes/origin/master            7e2b36e Merge pull request #160 from tomdee/tiny-build-image-size-tweaks
    remotes/origin/mcp               25fd9c2 Fix .gitreview


2. withMerge = true
  $ git status
  On branch mcp
  nothing to commit, working directory clean
  $ git branch -av
  * mcp                              25fd9c2 Fix .gitreview
    remotes/origin/HEAD              7e2b36e Merge pull request #160 from tomdee/tiny-build-image-size-tweaks
    remotes/origin/develop           013614f Merge pull request #144 from djosborne/comment-etcd-pin
    remotes/origin/feature/utreports 3c52c2a disable usage reports while running unit tests
    remotes/origin/go                350e251 Merge pull request #128 from caseydavenport/ipam-code-review
    remotes/origin/master            7e2b36e Merge pull request #160 from tomdee/tiny-build-image-size-tweaks
    remotes/origin/mcp               25fd9c2 Fix .gitreview