Streamly is a Haskell library that marries monadic streaming and concurrency
providing an elegant way of doing declarative concurrent dataflow programming.
The Haskell ecosystem has some fine streaming libraries like pipes and conduit.
However, these libraries are inherently serial and provide no support for
concurrency within the streaming framework. Streamly is the first ever haskell
streaming library that defines and implements concurrency semantics within
a monadic streaming framework.

The streaming API of Streamly is surprisingly simple, it is almost the same as
standard Haskell lists, therefore, programmers do not need to learn a new DSL.
By using specific concurrency-style combinators, streams can be generated,
merged, chained, mapped, zipped, and consumed concurrently. Imagine your
program as a pipeline of queues composed in a combination of serial and
parallel configurations, and you can easily control which of these queues to
run concurrently and at what rate. The degree of concurrency is auto scaled
based on the feedback from the stream consumer, or based on a programmer
specified rate limit. Moreover, Streamly does not trade performance with high
level declarative concurrency, it provides excellent non-concurrent and
concurrent performance.

Haskell can and does perform as well as C, sometimes even better. However,
writing high performance software in Haskell is often challenging especially
because performance is sensitive to strictness, inlining and specialization.
This talk focuses on how to write high performance code using Haskell. It is
derived from practical experience writing high performance Haskell libraries. We
will go over some of the experiences from optimizing the "unicode-transforms"
library whose performance rivals the best C library for unicode normalization.
From more recent past, we will go over some learnings from optimizing and
benchmarking "streamly", a high performance concurrent streaming library. We
will discuss systematic approach towards performances improvement, pitfalls and
the tools of the trade.