before returning). There are many styles of asynchronous interfaces: Callback argument Return a placeholder (Future, Promise, Deferred) Deliver to a queue Callback registry (e.g. POSIX signals) Regardless 5/library/concurrent.futures.html#module- concurrent.futures] package. class tornado.concurrent.Future Placeholder for an asynchronous result. A Future encapsulates the result of an asynchronous operation. In org/3.5/library/string.html#module- string]) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low-level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless functions for interacting with the concurrent.futures package. class tornado.concurrent.Future Placeholder for an asynchronous result. A Future encapsulates the result of an asynchronous operation. In level to terminal color code • datefmt (string) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low-level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low-level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low- level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. 150 Chapter 6. Documentation Tornado Documentation, Release 6.4 Changed in version

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low- level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low- level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. 150 Chapter 6. Documentation Tornado Documentation, Release 6.4 Changed in version

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low- level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. 150 Chapter 6. Documentation Tornado Documentation, Release 6.4 Changed in version

returning). There are many styles of asynchronous interfaces: • Callback argument • Return a placeholder (Future, Promise, Deferred) • Deliver to a queue • Callback registry (e.g. POSIX signals) Regardless do not actually make things asynchronous). Asynchronous operations in Tornado generally return placeholder objects (Futures), with the exception of some low- level components like the IOLoop that use callbacks level to terminal color code • datefmt (str) – Datetime format. Used for formatting (asctime) placeholder in prefix_fmt. Changed in version 3.2: Added fmt and datefmt arguments. tornado.log.enable_p