A key of this coroutine context element.

abstract val key: Key<*>

Accumulates entries of this context starting with initial value and applying operation from left to right to current accumulator value and each element of this context.

open fun <R> fold(
    initial: R, 
    operation: (R, Element) -> R
): R

Returns the element with the given key from this context or null. Keys are compared by reference, that is to get an element from the context the reference to its actual key object must be presented to this function.

open operator fun <E : Element> get(key: Key<E>): E?

Returns a context containing elements from this context, but without an element with the specified key. Keys are compared by reference, that is to remove an element from the context the reference to its actual key object must be presented to this function.

open fun minusKey(key: Key<*>): CoroutineContext