* same result.
   */
  enum CollectStrategy {
    /** Get one accumulator and accumulate the elements into it sequentially. */
    SEQUENTIAL {
      @Override
      final <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>
          A result(Collector<T, A, R> collector, Iterable<T> inputs) {

  val mappingsBuffer = StringBuilder()
  val sectionIndexBuffer = Buffer()

  var previousMappedRanges: List<MappedRange>? = null

  for ((section, sectionMappedRanges) in sections) {
    // Skip sequential ranges when they are equal.
    if (sectionMappedRanges == previousMappedRanges) continue
    previousMappedRanges = sectionMappedRanges

    val sectionOffset = rangesBuffer.size.toInt() / 4

    // Section prefix.

This is necessary for bookkeeping when creating new streams. Correct framing requires that stream IDs are sequential on the socket, so we need to bundle assigning the ID with sending the `SYN_STREAM` frame.

## Connection Pool

package okhttp3.internal.concurrent

import java.util.concurrent.CountDownLatch
import java.util.concurrent.RejectedExecutionException
import okhttp3.internal.okHttpName

/**
 * A set of tasks that are executed in sequential order.
 *
 * Work within queues is not concurrent. This is equivalent to each queue having a dedicated thread
 * for its work; in practice a set of queues may share a set of threads to save resources.
 */

   * same result.
   */
  @IgnoreJRERequirement // *should* be redundant with the one on CollectorTester
  enum CollectStrategy {
    /** Get one accumulator and accumulate the elements into it sequentially. */
    SEQUENTIAL {
      @Override
      final <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>
          A result(Collector<T, A, R> collector, Iterable<T> inputs) {

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[14] *}

O `.add_task()` recebe como argumentos:

* Uma função de tarefa a ser executada em segundo plano (`write_notification`).
* Qualquer sequência de argumentos que deve ser passada para a função de tarefa na ordem (`email`).
* Quaisquer argumentos nomeados que devem ser passados para a função de tarefa (`message="some notification"`).

For "synchronous" (contrary to "asynchronous") they commonly also use the term "sequential", because the computer / program follows all the steps in sequence before switching to a different task, even if those steps involve waiting.

### Concurrency and Burgers { #concurrency-and-burgers }

import java.util.concurrent.Executors
import java.util.concurrent.TimeUnit
import java.util.logging.Logger
import okhttp3.TestUtil.threadFactory

/**
 * Runs a [TaskRunner] in a controlled environment so that everything is sequential and
 * deterministic.
 *
 * This class ensures that at most one thread is running at a time. This is initially the JUnit test
 * thread, which yields its execution privilege while calling [runTasks], [runNextTask], or

Si los passwords no coinciden, devolvemos el mismo error.

#### Hashing de passwords { #password-hashing }

"Hacer hash" significa: convertir algún contenido (un password en este caso) en una secuencia de bytes (solo un string) que parece un galimatías.

Siempre que pases exactamente el mismo contenido (exactamente el mismo password) obtienes exactamente el mismo galimatías.

		default:
			return nil, ErrUnsignedHeaders
		}
	}
	return extractedSignedHeaders, ErrNone
}

// Trim leading and trailing spaces and replace sequential spaces with one space, following Trimall()
// in http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html
func signV4TrimAll(input string) string {
	// Compress adjacent spaces (a space is determined by