list类型的命令。主要包括以下几个
lpush key value[value …]
lpop key value
rpush key value [value …]
rpop key value
llen key value
lrange key low high
rpushx key value
lpushx key value
lrem key count value
lset key index value
lindex key index
linsert key before/after pivot value
rpoplpush source destination
blpop key[key …] timeout
brpop key[key …] timeout
brpoplpush source destination timeout
ltrim key low high
