await do_stuff()
```

When you create a context manager or an async context manager like above, what it does is that, before entering the `with` block, it will execute the code before the `yield`, and after exiting the `with` block, it will execute the code after the `yield`.

In our code example above, we don't use it directly, but we pass it to FastAPI for it to use it.

    public void test_update() throws Exception {
        writeTestFile("a,b => c\nd,e => f\n");

        // Get existing item
        OptionalEntity<CharMappingItem> existing = charMappingFile.get(1L);
        assertTrue(existing.isPresent());

        // Update the item
        CharMappingItem updateItem = existing.get();
        updateItem.setNewInputs(new String[] { "m", "n" });
        updateItem.setNewOutput("o");

In this scenario of "fast food burgers with your crush", as there is a lot of waiting 🕙, it makes a lot more sense to have a concurrent system ⏸🔀⏯.

This is the case for most of the web applications.

Many, many users, but your server is waiting 🕙 for their not-so-good connection to send their requests.

And then waiting 🕙 again for the responses to come back.

        FileUtil.writeBytes(file.getAbsolutePath(), "ldap.security.principal=******@****.***".getBytes("UTF-8"));
        DynamicProperties systemProps = new DynamicProperties(file);

        // Get existing component and update it instead of registering new one
        DynamicProperties existingProps = SingletonLaContainerFactory.getContainer().getComponent("systemProperties");

        facetInfo.addQuery("query1");
        assertNotNull(facetInfo.query);
        assertEquals(1, facetInfo.query.length);
        assertEquals("query1", facetInfo.query[0]);
    }

    // Test addQuery with existing queries
    public void test_addQuery_existingQueries() {
        facetInfo.query = new String[] { "query1", "query2" };
        facetInfo.addQuery("query3");
        assertNotNull(facetInfo.query);

    /**
     * Read bytes from the input stream into a buffer
     *
     * @param in the input stream to read from
     * @param b the buffer to read into
     * @param off the offset in the buffer to start writing
     * @param len the number of bytes to read
     * @return number of bytes read
     * @throws IOException if an I/O error occurs
     */

 * <td>
 * Open the Named Pipe foo for reading and writing. The pipe will behave like the <code>CallNamedPipe</code> interface.
 * </td>
 * </tr>
 * <tr>
 * <td >
 *
 * <pre>
 * new SmbNamedPipe("smb://server/IPC$/foo", SmbNamedPipe.PIPE_TYPE_RDWR | SmbNamedPipe.PIPE_TYPE_TRANSACT, context);
 * </pre>
 *
 * </td>
 * <td>
 * Open the Named Pipe foo for reading and writing. The pipe will behave like the <code>TransactNamedPipe</code>

     */
    @JvmStatic
    @JvmName("enqueue")
    fun Call.enqueueEventSource(listener: EventSourceListener): EventSource = RealEventSource(this, listener).also(this::enqueue)

    /**
     * Processes the existing response with [listener].
     */
    @JvmStatic
    @JvmName("process")
    fun Response.processEventSource(listener: EventSourceListener) = RealEventSource(this, listener).processResponse(this)
  }

 * </pre></td><td>
 * Open the Named Pipe foo for reading and writing. The pipe will behave like the <code>CallNamedPipe</code> interface.
 * </td></tr>
 * <tr><td ><pre>
 * new SmbNamedPipe( "smb1://server/IPC$/foo",
 *         SmbNamedPipe.PIPE_TYPE_RDWR |
 *         SmbNamedPipe.PIPE_TYPE_TRANSACT );
 * </pre></td><td>
 * Open the Named Pipe foo for reading and writing. The pipe will behave like the <code>TransactNamedPipe</code> interface.

        } catch (RuntimeException e) {
            assertEquals("Change password failed", e.getMessage());
        }

        assertEquals(1, chain.changePasswordCalls.size());
    }

    // Test load with existing user
    public void test_load_existingUser() {
        TestAuthenticationChain chain = new TestAuthenticationChain();
        User inputUser = createTestUser("inputuser", "Input User");