Add pipeline and transaction

[CahidArda]

Adding pipeline and transaction feature as described in #45.

Majority of the update is complete. Next steps:

• Docstrings
• Context manager usage (with redis.pipeline() as pipe: ...)
• Benchmarking
• Auto pipelining for asyncio

[linear]

DX-882 Add transactions and pipeline support to Python SDK

[CahidArda]

to benchmark the pipeline, I tried sending 100 incrby commands back to back

Code

Pure redis:

t1 = time.time()
iter_count = 100
for i in range(iter_count):
    redis.incrby("marine", 10)
val = redis.get("marine")
assert val == str(iter_count*10)

t2 = time.time()
print(t2-t1)

Pipeline:

import time

t1 = time.time()
iter_count = 100
with redis.multi() as pipeline:
    for i in range(iter_count):
        pipeline.incrby("marine", 10)
val = redis.get("marine")
assert val == str(iter_count*10)

t2 = time.time()
print(t2-t1)

Runtimes:

Normal	Pipeline	Transcation
5.28 s	0.31 s	0.34 s