ZLayer provided a very clean solution to the problems developers were havingwith ZIO Environment—not perfect, mind you, and I don’t think any solutionprior to Scala 3 can be perfect (every solution in the design space has differenttradeoffs). This solution became even better when the excellent consultancySeptimal Mind donated Izumi Reflect to the ZIO organization

Has can be thought of as a type-indexed heterogeneous map, which is type safe,but requires access to compile-time type tag information. ZLayer can be thoughtof as a more powerful version of Java and Scala constructors, which can buildmultiple services in terms of their dependencies.