[Improve][Producer] Refactor internalSend() and resouce managment

[gunli]

Fixes #1043

Master Issue:

• [Improve][Producer]Simplify the MaxPendingMessages controlling #1043
• [fix] [issue 1051]: Fix inaccurate producer mem limit in chunking and schema #1055
• [Fix][producer] Fail all messages that are pending requests when closing like java #1059
• [Bug][Producer]Inaccurate transaction endSendOrAckOp for chunked message #1060
• [BUG] The capacity of dataChan is too big #1067
• [fix] [issue 1067] Fix the excessive dataChan capacity #1068

Motivation

1. As discussed in [fix] [issue 1051]: Fix inaccurate producer mem limit in chunking and schema #1055, we need to calculate how many pending items and how many memory are required before appending the sendRequest to the dataChan, but currently, we do schema-encoding/compressing in internalSend(), this may lead to inaccurate memory limit cotrolling, and as described in [Improve][Producer]Simplify the MaxPendingMessages controlling #1043, make the code complicated and difficult to maintain, we need to simplify the send logic;
2. In JAVA client, schema-encoding/compressing are done in application thread, it better to make it work like JAVA client;
3. As discussed in [fix] [issue 1051]: Fix inaccurate producer mem limit in chunking and schema #1055 and described in [Improve][Producer]Simplify the MaxPendingMessages controlling #1043, resource(memory and semaphore) acquiring/releasing logic are written across the whole file, we need to simplify the resource management logic, encapsulate them into functions, call them when necessary, make it 'Low Coupling, High Cohesion';
4. As discussed in [Bug][Producer]Inaccurate transaction endSendOrAckOp for chunked message #1060, transaction is not correctly ended for chunked message, it better to encapsulate the transaction ending logic into one func which will be called when sendRequest is done.

Modifications

1. Move shema encoding from internalSend() to internalSendAsync();
2. Move compressing from internalSend() to internalSendAsync();
3. Calculate total chunks before entering the dataChan;
4. Reserve required semaphore and memory before entering the dataChan;
5. sendRequest store the semaphore and memory it holds;
6. Encapsualte relative code blocks into individual funcs to make the skeleton of internalSendAsync() clearer;
7. Add sendRequest.done() to release the resources it holds;
8. When a sendRequest is done, call sendRequest.done() ;
9. In sendRequest.done() run callback, update metrics, end transaction, run interceptors callback...

Verifying this change

• Make sure that the change passes the CI checks.

This change is already covered by existing tests, such as (please describe tests).

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: (no)
• The schema: (no)
• The default values of configurations: (no)
• The wire protocol: (no)

Documentation

• Does this pull request introduce a new feature? no)
• If yes, how is the feature documented? (not applicable / docs / GoDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a followup issue for adding the documentation

[gunli]

@tisonkun @RobertIndie @Gleiphir2769 @nodece

[tisonkun]

Splitted. I'll convey your credit as Co-authored-by.