OR-5257 FilteringOperators:: Dropping values

[crazymanish]

Context

• Close ticket: [w21(21may-27may)] Operators:: Filtering Operators: Dropping values #21

Operators are publishers

• In Combine, methods that perform an operation on values coming from a publisher are called operators.
• Each Combine operator actually returns a publisher. Generally speaking, that publisher receives the upstream values, manipulates the data, and then sends that data downstream.

In this PR

• FilteringOperators:: Dropping values
• We can use it when we want to ignore values from one publisher until a second one starts publishing,
• or if we want to ignore a specific amount of values at the start of the stream.

---

• dropFirst(_:) Omits the specified number of elements before republishing subsequent elements.
• https://developer.apple.com/documentation/combine/publishers/collect/dropfirst(_:)
• drop(while:) Omits elements from the upstream publisher until a given closure returns false, before republishing all remaining elements.
• https://developer.apple.com/documentation/combine/publishers/collect/drop(while:)
• tryDrop(while:) Omits elements from the upstream publisher until an error-throwing closure returns false, before republishing all remaining elements.
• https://developer.apple.com/documentation/combine/publishers/collect/trydrop(while:)
• drop(untilOutputFrom:) Ignores elements from the upstream publisher until it receives an element from a second publisher.
• https://developer.apple.com/documentation/combine/publishers/collect/drop(untiloutputfrom:)