new EqualsTester()
        .addEqualityGroup(
            Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("foo")),
            Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("foo")))
        .addEqualityGroup(Suppliers.compose(Functions.constant(2), Suppliers.ofInstance("foo")))
        .addEqualityGroup(Suppliers.compose(Functions.constant(1), Suppliers.ofInstance("bar")))
        .testEquals();
  }

For example:

	// #cgo noescape cFunctionName

When a Go function calls a C function, it prepares for the C function to
call back to a Go function. The #cgo nocallback directive may be used to
tell the compiler that these preparations are not necessary.
If the nocallback directive is used and the C function does call back into
Go code, the program will panic.

For example:

The [bytes] package adds several functions that work with iterators:
- [Lines] returns an iterator over the
  newline-terminated lines in the byte slice s.
- [SplitSeq] returns an iterator over
  all substrings of s separated by sep.
- [SplitAfterSeq] returns an iterator
  over substrings of s split after each instance of sep.
- [FieldsSeq] returns an iterator over
  substrings of s split around runs of whitespace characters,
  as defined by unicode.IsSpace.

 * **Route**: address, proxy, socketAddress
 * **TlsVersion**: javaName

#### Renamed Functions

* **Headers.of()**: for symmetry with `listOf()`, `setOf()`, etc., we’ve replaced
  `Headers.of(String...)` with `headersOf(vararg String)`.

#### Extension Functions

We’ve migrated from static functions to extension functions where we think they fit.

| Java                                | Kotlin                          |

	}
	// cleaning up the backend by removing all the directories and files created on function return.
	defer removeRoots(disks)

	// uses *testing.B and the object Layer to run the benchmark.
	runPutObjectPartBenchmark(b, objLayer, objSize)
}

// creates Erasure/FS backend setup, obtains the object layer and calls the runPutObjectBenchmark function.
func benchmarkPutObject(b *testing.B, instanceType string, objSize int) {

    <function-class>org.codelibs.fess.taglib.FessFunctions</function-class>
    <function-signature>java.lang.String sdh(java.lang.String)</function-signature>
    <example>${fe:sdh(doc.similar_docs_hash)}</example>
  </function>

  <function>
    <description>Concatenate strings.</description>
    <name>join</name>
    <function-class>org.codelibs.fess.taglib.FessFunctions</function-class>

  public void testTransform_absent() {
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.identity()));
    assertEquals(Optional.absent(), Optional.absent().transform(Functions.toStringFunction()));
  }

  public void testTransform_presentIdentity() {
    assertEquals(Optional.of("a"), Optional.of("a").transform(Functions.identity()));
  }

  public void testTransform_presentToString() {

    }
    return nodeConnections.buildOrThrow();
  }

  @SuppressWarnings("unchecked")
  private static <N> GraphConnections<N, Presence> connectionsOf(Graph<N> graph, N node) {
    Function<N, Presence> edgeValueFn =
        (Function<N, Presence>) Functions.constant(Presence.EDGE_EXISTS);
    return graph.isDirected()
        ? DirectedGraphConnections.ofImmutable(node, graph.incidentEdges(node), edgeValueFn)

//     grad_outputs[1]->Ref();
//     return OkStatus();
//   }
//   ~AddGradientFunction() override {}
// };
//
// GradientFunction* AddRegisterer(const ForwardOperation& op) {
//   // More complex gradient functions can use inputs/attrs etc. from the
//   // forward `op`.
//   return new AddGradientFunction;
// }
//
// Status RegisterGradients(GradientRegistry* registry) {
//   return registry->Register("Add", AddRegisterer);

You can define event handlers (functions) that need to be executed before the application starts up, or when the application is shutting down.

These functions can be declared with `async def` or normal `def`.

### `startup` event

To add a function that should be run before the application starts, declare it with the event `"startup"`: